Party's over: Diwali leaves Delhi wheezing in dangerously unhealthy air

The Air Quality Index surged to 451 on a scale of 500 - the maximum recorded this year - indicating 'severe' conditions that affect healthy people and seriously impacts those with existing diseases

The morning after Diwali, the Hindu festival of lights, residents of New Delhi woke up under a blanket of toxic smog and breathed in the most dangerously polluted air of the year so far, after revellers, as usual, defied a fireworks ban.

New Delhi has the worst air quality of all world capitals, but even by its sorry standards Friday's reading was extra bad, as people paid the price for celebrating India's biggest festival in the noisiest, and most smoky way.

The Air Quality Index (AQI) surged to 451 on a scale of 500 - the maximum recorded this year - indicating