1001 Smart Cities

Permanent project revision

Ultra Low Emission Zone (ULEZ)

Revision 2026-10-11-deep-run · effective 2026-10-11

Current revision. This is the snapshot used by the live entity page.

unreviewed

Deep Run 2026-10-11: every source re-read and dated, present-tense statements dated, claim array completed; impact: Crossref (DOI 10.1038/s44407-025-00030-9) lists Chengxu Tong as first author; Robert J. R. Elliott is the fourth of seven. The existing claim quotes the wrong name, so it changes with this correction.; sources: Same wrong first author in the label; the editor renames both ends (claim array references it).; lesson: "Clean-air zones work" generalises from one city, and "expansion needs early, honest communication with affected drivers" is carried by no listed source. The new lesson keeps the diminishing-returns point and grounds it in the study and the University of Birmingham release, a

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All revisions → Current entity page →

Change set

  • replace /snapshot/projectFingerprint — Updated projectFingerprint to the current sourced project record.
  • replace /snapshot/asOf — Updated asOf to the current sourced project record.
  • replace /snapshot/claims — Updated claims to the current sourced project record.
  • replace /snapshot/sources — Updated sources to the current sourced project record.
11
of 11 claims mapped
7
source dossiers
4
publication dates recorded
1
archives linked
0
exact locators
0
content captures hashed

Claims, one by one

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-524c2edae3829e18 quantitative
London's Ultra Low Emission Zone charges the most polluting vehicles £12.50 a day
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: vehicles that do not meet the standards "must pay a charge of £12.50 per day to travel in the ULEZ if they are not otherwise subject to a grace period, discount, or exemption." The RAC's 2026 guide gives the same £12.50 daily charge.
Caveat
The charge applies to vehicles that do not meet the ULEZ emission standards, not to a list of 'most polluting' models.

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
  2. RAC — ULEZ guide 2026 (press)
Claim 2 clm-22bc36dc93fcaccc quantitative
Launched in central London in April 2019
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: the T-Charge "was replaced by the introduction of the ULEZ in central London in April 2019".
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
Claim 3 clm-924879aa263660ca quantitative
expanded to all London boroughs in August 2023
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: "On 29 August 2023, the Mayor of London expanded the Ultra Low Emission Zone (ULEZ) across all London boroughs".
Caveat
An intermediate expansion to inner London took effect in October 2021.

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
Claim 4 clm-96805ccdace598ac descriptive
it is what TfL calls the world's largest clean air zone
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: "The London-wide zone measures 1,500 km2 and covers nine million people, making it the largest zone of its kind in the world."
Caveat
The superlative is TfL's own claim.

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
Claim 5 clm-c34f8bbd3cef7c19 descriptive
enforced around the clock by automatic number-plate cameras
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: "The ULEZ operates 24 hours a day, every day of the year except Christmas Day", and compliance is measured from "TfL's Automatic Number Plate Recognition (ANPR) camera network", with around 3,900 cameras across the London-wide zone. The RAC's 2026 guide confirms the 24-hour operation.
Caveat
The zone does not operate on Christmas Day.

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
  2. RAC — ULEZ guide 2026 (press)
Claim 6 clm-0b46dd1cfecd4222 quantitative
TfL estimates roadside NO2 in 2024 was 27% lower across London than without the ULEZ (54% lower in central London)
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: in 2024, compared to a scenario without the ULEZ, harmful roadside NO2 concentrations are estimated to be "27 per cent lower across the whole of London" and "54 per cent lower in central London than they would have been without the ULEZ and its expansions."
Caveat
These are TfL's modelled estimates against a no-ULEZ scenario, not measured before-and-after changes.

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
Claim 7 clm-b26255088c710f16 quantitative
~80% fewer people in the most deprived areas near busy roads were exposed to illegal pollution levels (One Year Report, March 2025)
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
TfL's One Year Report: "for some of the most deprived communities living near London's busiest roads, there's been an estimated 80 per cent reduction in people exposed to illegal levels of pollution."
Caveat
TfL's estimate refers to some of the most deprived communities along the TfL road network, against a no-ULEZ scenario.

Sources carrying this claim

  1. TfL — ULEZ One Year Report (authority)
Claim 8 clm-bdeb3d95fd5c85d3 quantitative
An independent peer-reviewed study (Tong et al., npj Clean Air, 2025) measured a more modest ~19.6% NO2 cut at central-London traffic sites after the 2019 zone, and no detectable effect from the 2023 outer expansion
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The study: "We found that the 2019 ULEZ led to 19.6% and 8.2% (~13.3 and 2.7 µg m−3) reductions in nitrogen dioxide (NO2) at traffic and urban background sites, respectively, in the three months after its implementation within central London" and "the ULEZ 2023 expansion showed no detectable impact on NO2."
Caveat
The 19.6% is the three-month effect (17.8% after 11 months). The two estimates are not directly comparable: TfL models 2024 against a no-ULEZ scenario, the study measures the change after each phase. TfL's own One Year Report estimates larger effects — roadside NO2 27% lower across London in 2024 and 54% lower in central London.

Sources carrying this claim

  1. Tong et al. 2025, npj Clean Air (peer-reviewed)
  2. University of Birmingham (research)
Claim 9 clm-c3ed7c44f7b000b7 descriptive
Returns diminish once most vehicles already comply
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The University of Birmingham's headline: "London's ULEZ cut air pollution — high vehicle compliance left little room for post-expansion gains".
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. University of Birmingham (research)
  2. Tong et al. 2025, npj Clean Air (peer-reviewed)
Claim 10 clm-b829437b268c789c quantitative
by the 2023 London-wide expansion only 7.4% of vehicles on London's roads were non-compliant, and the independent study found no detectable NO2 effect from that expansion
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
University of Birmingham: "By the time the ULEZ expansion was introduced in 2023, only 7.4% of vehicles on the road across London were classified as non-compliant"; the study: "the ULEZ 2023 expansion showed no detectable impact on NO2".
Caveat
The 7.4% is the study's reading of TfL vehicle data; TfL's own report gives compliance of 91.6% in June 2023 for vehicles subject to the standards, a different base.

Sources carrying this claim

  1. University of Birmingham (research)
  2. Tong et al. 2025, npj Clean Air (peer-reviewed)
Claim 11 clm-8dcbb45ccef8359b quantitative
It also found no significant benefit for fine particles (PM2.5), and its authors conclude that the ULEZ alone is insufficient to clean London's air
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The study: "we found no significant benefits of ULEZ on fine particle (PM2.5)" and "Our results illustrate that ULEZ alone is insufficient to clean up the air in London".
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Tong et al. 2025, npj Clean Air (peer-reviewed)

Source dossiers and revision state

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-10-11-deep-run effective 2026-10-11 · created 2026-10-11

Awaiting operator and domain-expert review; publication of this revision implies neither.

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Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
11
of 11 claims mapped
7
source dossiers
4
publication dates recorded
1
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Transport for London (TfL)
Actor types
utility
Funding model
public
Funding description
Not recorded
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

7 source dossiers

Transport for London (authority) tfl.gov.uk · background

Open original source ↗

Stable source ID
src-97ebd5d47555d6c4
Publisher
Name not classified · tfl.gov.uk
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

TfL's ULEZ page: the daily charge, the vehicle standards, operating hours and the zone map.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Londonist (press) londonist.com · background

Open original source ↗

Stable source ID
src-e88e34ca2954c7d0
Publisher
Name not classified · londonist.com
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

News coverage of the August 2023 London-wide expansion.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Centre for Cities (think tank) centreforcities.org · background

Open original source ↗

Stable source ID
src-db296f845b951877
Publisher
Name not classified · centreforcities.org
Type / language
web-page · language not classified
Published
2022-12-01
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Think-tank blog (1 December 2022) welcoming the decision to extend the zone London-wide from August 2023 at £12.50 a day, and noting the £110m scrappage scheme for targeted groups.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
University of Birmingham (research) birmingham.ac.uk · 3 linked claims

Open original source ↗

Stable source ID
src-53095389fb730e09
Publisher
Name not classified · birmingham.ac.uk
Type / language
web-page · language not classified
Published
2025-10-22
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

University of Birmingham release (22 October 2025) on the npj Clean Air study: NO2 fell 19.6% at roadside sites in central London within three months of the 2019 zone, no significant effect on NO2 or NOx after the 2023 expansion, and only 7.4% of vehicles on London's roads were non-compliant by the time of that expansion.

Descriptive only — not page/paragraph exact
Claims linked
TfL — ULEZ One Year Report (authority) content.tfl.gov.uk · 7 linked claims

Open original source ↗

Stable source ID
src-f761866c1d1f34a3
Publisher
Name not classified · content.tfl.gov.uk
Type / language
pdf · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

TfL's evaluation of the first year of the London-wide zone (March 2025): roadside NO2 in 2024 estimated 27% lower across London and 54% lower in central London than without the ULEZ, an estimated 80% fewer people exposed to illegal NO2 levels in some of the most deprived communities near the busiest roads, a £12.50 daily charge, 24-hour operation every day except Christmas Day, ANPR camera enforcement, and the zone described as the largest of its kind in the world.

Descriptive only — not page/paragraph exact
Claims linked
Tong et al. 2025, npj Clean Air (peer-reviewed) nature.com · 4 linked claims

Open original source ↗

Stable source ID
src-22d3b2b43309a95b
Publisher
Name not classified · nature.com
Type / language
web-page · language not classified
Published
2025-10-22
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
Open archived copy ↗ · 2025-10-22
Content hash
No captured content hash
Locator
Open the recorded source note

Peer-reviewed causal study by Tong, Dai, Cole, Elliott, Bartington, Liu and Shi (University of Birmingham): the 2019 ULEZ cut NO2 by 19.6% at central-London traffic sites in the first three months (17.8% after 11 months), the 2023 expansion showed no detectable impact on NO2, and no significant benefit for PM2.5 was found; the authors conclude the ULEZ alone is insufficient to clean up London's air.

Descriptive only — not page/paragraph exact
Claims linked
RAC — ULEZ guide 2026 (press) rac.co.uk · 2 linked claims

Open original source ↗

Stable source ID
src-fa467c502957477f
Publisher
Name not classified · rac.co.uk
Type / language
web-page · language not classified
Published
2026-01-22
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-11
Dossier created
2026-10-11
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Motoring guide for 2026: non-compliant cars, motorcycles and vans pay a £12.50 daily charge, and the zone operates 24 hours a day, every day except Christmas Day, covering almost all of Greater London.

Descriptive only — not page/paragraph exact
Claims linked
Known limits of this file
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.