As the world discusses climate change in Paris, this is the hazardous smog engulfing New Delhi

On Dec. 1, as talks on climate change entered their second day in Paris, the Indian capital of New Delhi was enveloped in thick smog.

The air quality index in the city rose to 372, putting Delhi’s air in the hazardous category, according to the US embassy’s monitoring station. Visibility in the city was down to about 200 yards after the thick smog set in.

Much of the heavy smog that has inundated the city since early November is due to the increased usage of coal fire to fight the onset of winter and the burning of paddy straw at farms in adjoining states.

But historic data indicates a long, troubling trend. Versus just one fog day in 1951, New Delhi sees in excess of 70 fog days annually during winter, largely due to rapid urbanization.

Here is how New Delhi has looked since early November, when the smog set in: