In mid january air quality in Beijing was so bad that it closed four major highways.
Harmful fine particulate matter PM2.5 was 500 in Beijing.
But it neared and crossed 300 in Delhi eight times in January.
Particulate matter which is less than 2.5 in diameter penetrates deeply into our lungs.
In three weeks the PM2.5 was less than 300 just for one day in the first three weeks of the year , a level which is 12 times the prescribed limit by WHO.
PM10 in 2011 in Beijing was avg 117 were as in Delhi it was 281.
Delhi's peak fine partculate matter is 44% higher this year compared to last year.
India's air quality is among the worst in the world.