Why Sadiq Khan can’t release ULEZ data right now and has to wait until after election

Sadiq Khan has said the publication of the latest report into the effect of last year’s expansion of ULEZ has had on air quality cannot go ahead until after the mayoral election on May 2. This is due to purdah, a period of time immediately before votes when specific restrictions on communications activity are in place.

The Mayor of London also said that the timing of publishing of the latest figures regarding the expansion of the £12.50 fee to outer boroughs in August was in line with previous enlargements of the scheme to Central and Inner London. In addition, he slammed claims from critics that a reduction in harmful emissions in the capital were not down to his policies.

Mr Khan told MyLondon: “If you look at the last two ULEZs that we’ve had in Central London and Inner London, TfL published air quality data for a six month period once they have been peer reviewed and so forth. That often happened a number of months after the six months.”

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Referencing the Central London report, Mr Khan said that it was not published wasn’t published on six months, but six months plus nine months, ‘roughly speaking’. This is because it ‘takes some time’ for the review to take place.

The same applied, the mayor added, to the Inner London expansion report. He said: “The six months for the ULEZ expansion was very recently. TfL are getting in the data.

“They’ll be analysing the data, they’ll ensuring that data is peer reviewed and then they’ll publish the data. Unfortunately, because of the pre-election period, it won’t happen before the election.”

Report ‘can’t be published during pre-election period’

Mr Khan then referenced separate data published by City Hall last week stating that annual concentrations of roadside nitrogen dioxide (NO2) were much higher in London than the rest of the UK in 2016, but these have ‘almost halved’ in London between 2016 and 2023. This is compared to 35 per cent across rest of England, officials say.

The study states that preliminary figures indicate London’s annual NO₂ levels were lowest on record in 2023 – lower even than first year of COVID-19 lockdowns.

But the BBC reports that the Liberal Democrats have claimed that the report showed most of the improvements came before the ULEZ and were due to cleaner lorries, modernising the capital’s bus and taxi fleets, and people naturally getting rid of their more polluting vehicles.

‘Of course it’s my policies that have led to lower emissions’

The T-charge, for example, was introduced in 2017, buses had to comply with the Low Emission Zone (LEZ) by 2016 and lorry emission regulations were made stricter in 2012 and 2021. Mr Khan said: “Of course the reduction in air pollution has been because of my policies.

“It’s my policy to have low emission bus services. It’s my policies that have led to us having more than 1,300 zero emission buses. It’s my policies that have led to half of our taxi fleets being zero emission.

“My policies led to more walking and cycling. My policies that’s increased six fold the amount of cycle lanes. So of course the benefits from reduced air pollution are because of City Hall policies.”

Asked if he was optimistic about that the next report into the effect of the ULEZ expansion, the mayor added that previous analysis of the scheme in Central and Inner London have proven that ‘it works’. “We know it works”, Mr Khan said, “because of the reduction in nitrogen dioxide, nitrogen oxide and particulate matter.”

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