NEW DELHI (Reuters) -Air quality in India’s capital New Delhi deteriorated to hazardous levels on Tuesday with readings the highest in the world, according to Swiss group IQAir, partly due to the use of firecrackers during Diwali, the Hindu festival of lights.

The Supreme Court of India last week relaxed a ban on firecrackers in the city, permitting the use of so-called “green crackers” for a maximum three hours each on Sunday and Monday, although Reuters witnesses saw crackers being set-off outside the allotted times.

Emissions from the crackers are 30% to 50% lower than conventional fireworks.

IQAir’s reading for New Delhi was 442, making the Indian capital the world’s most polluted major city. Its PM 2.5 concentration was more than 59 times the World Health Organisation’s recommended

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