Stubble burning as seen from the sky in North India on October 28, 2018 (Photo courtesy: Nasa Worldview)

New Delhi and the surrounding national capital region (NCR) woke up to a thick haze and smog as the air quality over the region remained very poor like it does this time every year.

And things are about to get worse. Really worse.

Satellite images, provided by the US's National Aeronautics and Space Administration (Nasa), show that the whole of Punjab was essentially on fire yesterday (October 28). Well, the state's farms that is.

The satellite image you saw at the beginning of this story show instances of stubble burning in North India.

While Haryana -- an agrarian state like Punjab -- had stray incidents of stubble burning, Punjab was almost completely covered in red dots.

The government has previously said that the instances of stubble in Punjab and Haryana are fewer this year compared to last year.

Nasa satellite images from earlier this month showed that trend to be true. But the images since then have also shown another trend: The instances of stubble burning have markedly increased since the beginning of this month.

Take a look at this juxtaposition of satellite images taken on October and the one taken yesterday, October 28. The juxtaposition shows how stubble burning increased from minimal to covering the entire state of Punjab.

What is stubble burning?

A post-harvest practice used to clear fields of crop stubble.

The practice has been outlawed but due to lax implementation of the ban, stubble burning still takes place in North India

Farmers say in defence that they do not have any alternatives

State governments in agrarian states of Punjab and Haryana say that they do not get enough financial aid from the Centre to compensate the farmers

Here are some more Nasa satellite images showing how stubble burning has increased in North India during the past month:

Stubble burning as seen from the sky in North India on October 1, 2018 (Photo courtesy: Nasa Worldview)

Stubble burning as seen from the sky in North India on October 10, 2018 (Photo courtesy: Nasa Worldview)

Stubble burning as seen from the sky in North India on October 18, 2018 (Photo courtesy: Nasa Worldview)

Stubble burning as seen from the sky in North India on October 25, 2018 (Photo courtesy: Nasa Worldview)

Meanwhile, the air in New Delhi is currently so bad that prolonged exposure can lead to respiratory illnesses. And it is going to get worse.

Seen in this photo provided by prominent cardiovascular Dr Naresh Trehan is the lung of a person from Himachal Pradesh (left) and that of a person from New Delhi (right)

The months of winter spell annual trouble for New Delhi's air, which becomes highly polluted due to a number of reasons:

Weather and wind patterns

Stubble burning in agrarian states of Punjab and New Delhi

Vehicular and industrial pollution

Construction activity

The Air Quality Index for Delhi and NCR -- a number used to communicate the level of pollution in the air -- was recorded at 355.

This makes the air quality in Delhi and NCR "very poor" on the country's five-level air monitoring system.

A runner wearing a face mask takes part in the Airtel Delhi Half Marathon organised on October 21, 2018. (Photo: Reuters/Anushree Fadnavis)

The monitoring system qualifies the air from good to severe:

Good: AQI of 0-100; minimal impact on health

Satisfactory: AQI of 0-100; minor breathing discomfort to sensitive people

Moderate: AQI of 101-200; breathing discomfort to people with asthma, lung and heart diseases

Poor: AQI of 201-300; breathing discomfort to most people on prolonged exposure

Very poor: AQI of 301-400; respiratory illness on prolonged exposure

Severe: AQI of 401-500; affects healthy people and seriously impacts those with existing diseases

According to the government's System of Air Quality and Weather Forecasting And Research (Safar) the Air Quality Index of Delhi will inch towards the 400-mark in the upcoming days.





How stubble burning instances in North India have increased in the last 20 days or so (Gif via Giphy)

However, it will not become severe just yet. Still, Safar has issued a health advisory specifically for people suffering from heart or lung disease, older adults and children.

The advisory asks them to go for shorter walks instead of jogs, keep windows closed, and wear masks while stepping outside in order to lessen their exposure to the bad air.

IndiaToday.in will be tracking stubble burning instances and Delhi-NCR's air quality on a daily basis. Check our Air Quality page for the latest on this topic.

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