Delhi’s air has become toxic once again

BBC:

Every year, like clockwork, Delhi chokes.

A thick, toxic haze settles over the city – stinging eyes, burning throats and sending air quality monitors into panic mode.

For the past few days, the air in Delhi and its neighbouring satellite cities has hovered between the “poor” and “very poor” categories.

It worsened sharply after Diwali, one of India’s biggest festivals, as fireworks lit up the night sky and filled the air with smoke. Headlines reported that it was the worst post-Diwali air quality the city had experienced in the past four years.

With that, the city once again found itself confronting its annual, predictable – yet avoidable – crisis: air pollution.

There isn’t a single factor to blame for the toxic air.

It’s a combination of events – firecrackers, vehicular emissions and the burning of crop residue in the agrarian states of Punjab, Haryana and Uttar Pradesh – that leads to the same outcome every year. And as it coincides with the start of winter, colder temperatures and low wind speeds trap pollutants close to the ground.

This year too, the same factors are believed to be at play – although there are contradictory reports about what contributed how much to the toxic air this year.