BBC News: "Our reading for these minute, carcinogenic particles, which penetrate the lungs, entering straight into the blood stream - is a staggering 215 - 21 times recommended limits. And that's better than it's been all winter.
Until a few weeks ago, PM 2.5 levels rarely dipped below 300, which some here have described as an "air-pocalypse".
Like the rest of the world, those of us in Delhi believed for years that Beijing was the world's most polluted city.
But last May, the World Health Organization announced that our own air is nearly twice as toxic."