London consistently breaches WHO air quality limits; nitrogen dioxide (NO₂) from traffic is a major health risk.

Dense infrastructure traps heat, making central London several degrees warmer than surrounding areas.

The city produces over 7 million tons of waste annually, with limited landfill space and recycling inefficiencies.

When I visited, I saw almost no stars at night here.  

Light pollution here is the worst in the US.

At any given moment at night, in central New York City less than 15 stars are visible to the human eye. 

Public transport here is some of the worst; and so is pollution per capita. 

Less than 20 stars are visible here at night time by the human eye. 

But there was effort.