The introduction of pricing and fines to discourage the use of highly polluting vehicles in London has led to an improvement in school test scores for students in the LEZ, research published this week shows.

London has the largest LEZ in the world, covering all of the city’s boroughs, an area with nine million inhabitants.

Since the Greater London LEZ was introduced in 2008, there has been a meaningful improvement in the results of tests taken by students at the end of primary school, which can be linked to the zone, analysis from the London School of Economics (LSE) found.

“The magnitude of this effect is similar to reducing class size by ten students or paying teachers large financial bonuses,” said the authors of the report from the LSE’s Grantham Research Institute on Climate Change and the Environment.

The effect was greatest in schools serving a larger share of economically disadvantaged populations, the research found, highlighting the role of such policies in “levelling the educational playing field and supporting vulnerable communities”.

There is a well-documented link between air pollution and educational achievement, but there has been little research so far on the effects of clean air efforts on exam results.

The LEZ targets heavy diesel vehicles such as lorries, large vans and coaches, while the city also has an Ultra LEZ designed to deter any petrol and diesel vehicles that don’t meet emissions standards.

Studies have shown that these types of zones can improve health, including being linked to reductions in cardiovascular disease.