NEW DELHI - India's capital, New Delhi, was engulfed in thick smog early on Monday as cooler weather exacerbated pollution, even though government data showed that crop residue burning in neighbouring states had dropped significantly.

Residents of New Delhi and its suburbs endure poor air every winter as colder, heavier air traps construction dust, vehicle emissions and smoke from the burning of crop stubble in the nearby states of Punjab and Haryana.

However, paddy crop residue burning has reduced by 31% in the period from Sept. 15 till Nov. 30 this year, the government said in a statement on Monday.

The total number of farm fires in Punjab, Haryana and Delhi's suburbs fell to 53,792, owing to improved machinery and bio-decomposers to destroy crop residue, according to government data.

"Significant reduction in paddy crop residue burning events in the current year is reflective of vigorous and consistent efforts made by Central Government and State Governments and other stakeholders," the government said.

Environmentalists have often said that tackling farm fires alone will not clean Delhi's filthy air, which remained in the 'very poor' category on Monday.

The central government banned all private construction in the city and surrounding areas and enforced restrictions on diesel vehicles plying in the city. Authorities also sprayed water in some neighbourhoods to try to clear the air.

The government said that average daily air quality index has improved to 320.6 points in November, from 376.50 in November, 2021.

(Reporting by Tanvi Mehta; Editing by Robert Birsel and Toby Chopra)