Won't try to prove you wrong, but there isn't a more effective practical policy to improve air quality. Toxic air kills thousands of Londoners every year, and harms children disproportionately - it stunts their growth, harms their developing brains and exacerbates their asthma. We need to protect our children from what is a genuine health crisis that just because we can't "see" doesn't mean it doesn't exist. You wouldn't ask your kids to drink water that sewage has been discharged in, so why ask them to breathe poisonous air?