Introducing Ulez was my hardest decision as mayor of London – but now we know its astonishing impact | Sadiq Khan

London's Ultra Low Emission Zone has delivered measurable improvements in children's respiratory health, according to new research cited by Mayor Sadiq Khan.

The Ulez, introduced in 2016 as a clean air zone restricting high-polluting vehicles in central London, faced intense opposition from critics who characterized it as an attack on motorists. Khan defended the policy in light of emerging health data.

A recent study found that children living in London show improved lung size and function following the zone's implementation. The research provides the first biological evidence that the vehicle emissions restrictions translate directly into better respiratory outcomes for young residents.

London's air quality violated EU pollution standards for years before the Ulez launch. Nitrogen dioxide from diesel engines exceeded safe limits across much of the city. The zone charges vehicles that fail to meet emissions thresholds, effectively pushing older diesel and petrol cars off central London roads.

The lung function findings address the core public health rationale behind the policy. Children exposed to high pollution levels during critical lung development years face reduced respiratory capacity into adulthood. Khan emphasized that protecting children from dangerous pollution levels outweighed complaints from affected drivers.

The scheme expanded geographically over time, eventually covering much of Greater London. Initial skepticism gave way to measurable health gains, though implementation remained politically contentious.

The lung improvement data represents validation of Khan's approach in choosing environmental protection over political convenience. No other major city had attempted a comprehensive emissions zone of comparable scale when London launched Ulez. The health outcomes suggest the model merits replication elsewhere.

Transport authorities in other cities have since studied London's experience. The respiratory improvements documented in this study provide evidence-based justification for similar schemes facing their own local opposition.