India's pollution control authority has classified the air in Delhi as "severe plus", after the city passed 450 according to its measurements on Monday morning.

Authorities in India’s capital have shut schools, halted construction and banned non-essential trucks from entering the city after air pollution shot up to its worst level this season.

A thick, toxic smog has enveloped India's capital, home to more than 33 million people. One technology firm which monitors air pollution ranked New Delhi as the most polluted city in the world.

Delhi recorded air pollution more than 17 times above an acceptable level as worsening smog triggered curbs on trucking and shuttered construction sites and schools.

India said on Sunday that it would tighten restrictions including on construction activities and vehicle movements in New Delhi and surrounding areas from Monday to combat worsening air quality. The new measures,

Authorities in India’s capital have shut schools, halted construction and banned non-essential trucks from entering the city.

Delhi ’s government imposed the most stringent set of restrictions on the movement of vehicles and people as the toxic smog enveloping the Indian capital worsened on Monday. The city’s average air quality index was 457 in the morning,

The Indian capital closed all schools, banned lorries and halted construction work on Monday as air quality in New Delhi plummeted to its worst level this year, with a thick layer of yellowish haze engulfing the city of 22 million.