The Mayor said the level of dangerous particulates in the air has been reduced by 15% because of action on encouraging clean vehicles, walking and cycling. He also said he has introduced a plan to bring in an Ultra Low Emission Zone for vehicles in London by 2020.
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Calum McSwiggan posted a photo on Instagram as he lay in a hospital bed after the alleged attack.
The London mayor publicly backed defeated candidate Owen Smith in the contest which saw Mr Corbyn re-elected party leader.
Police described it as a "growing sink hole" and it's unclear when the road will reopen.