INDIA’S Supreme Court will hear a plea today demanding that authorities tackle the toxic smog gripping the capital and other cities across the country.

The plea coincides with sickening air pollution that is affecting New Delhi and has led the capital to shut schools and building sites.

Officials in the northern state of Uttar Pradesh said yesterday that they expect the acrid smog to blanket the state within days.

New Delhi’s skies have been filled for more than a week with a thick haze that has made people’s eyes sting and their throats sore.

Air pollution experts blame a range of pollution sources, from diesel-burning cars and seasonal crop burning to rubbish fires and stoves fuelled with kerosene and cow dung.

Winter weather patterns also mean there is less wind to circulate the air.

The smog “remains in the lower atmospheric layer,” said Dr Surya Kant Tripathi, who heads the pulmonary medicine department at King George’s Medical University in Lucknow, the Uttar Pradesh capital.

He urged people to avoid going outdoors, unless wearing face masks, warning: “Higher air pollution levels may take days to settle.”

The smog covering New Delhi is now expected to waft over western parts of Uttar Pradesh and eventually cover the entire state — India’s most populous area with around 210 million people.

In the Uttar Pradesh district of Ghaziabad, which is considered an eastern suburb of New Delhi, schools were closed yesterday and today, along with those in the capital.