10. Kanpur, India This industrial city was once known as the “Manchester of the East”, so it doesn't immediately fill you with visions of green meadows and clear waters. But the reality is grimmer than most imagined before the WHO results were published – Kanpur is the second most polluted city in India with a score of 209 ug/m3. It's the leather capital of the region, with a large tannery but it also has steel factoriesand many other industries.