High pollution warning issued in London as capital braces for 34C heat

Health experts have called for more to be done to tackle air pollution - (PA Archive)

A "high" air pollution alert for London has been issued by City Hall for Tuesday as sunny weather and high temperatures are expected to increase levels of toxic air.

Temperatures in the capital are expected to reach 34C, increasing ground-level ozone – a harmful pollutant which surges when heat and sunshine react with existing pollutants in the air.