Air pollution in India's national capital increased to 'severe' on an official index on Wednesday for the first time this season as temperatures and wind speeds dropped, reducing visibility and affecting some flights.

Every year, Delhi and northern states battle hazardous air during the winter months of October to January due to plummeting temperatures, smoke, dust, low wind speed, vehicular emissions and crop stubble burning. This time, experts say that the condition is likely to get worse in the coming days.

Delhi typically sees a spike in air pollution during the festive season starting in October. After Dussehra celebrations in the second week of October, Delhi’s Air Quality Index

The toxic smog that has enveloped India's capital worsened on Wednesday morning as temperatures and wind speeds dropped, reducing visibility and affecting flights. Delhi overtook Pakistan's Lahore as the world's most polluted city in Swiss group IQAir's live rankings,