Delhi smog: NASA pictures show heavy stubble burning, but is it really the villain here?

Apartments are shrouded by smog in Noida, India, December 14, 2016. REUTERS/Cathal McNaughton

Satellite images from National Aeronautics and Space Administration (NASA) over Punjab and Haryana in the last couple of weeks reveal some hard facts. The practice of crop stubble burning has been going on at an extensive level despite repeated warnings from Supreme Court and National Green Tribunal.

Scanning through the images capturing ‘Fires and Thermal Anomalies’ provided by NASA shows a pattern. Punjab and Haryana have two main growing seasons: one from May to September (Kharif) and another from November to April (Rabi). As soon as the Kharif crops are reaped, the farmers simply burn leftover plant debris, especially rice stubble to prepare the field for Rabi season.

“Every year, Punjab rice farms collectively burn about 7 to 8 million metric tons of leftover plant debris in October and November,” a NASA report says. These crop remains when burnt turn into fine particulate matter and helped by western winds, they reach Delhi to choke the city.

Also Read: Delhi chokes on deadly smog for second day, air quality recorded as 'hazardous' again

Every year, the first instances of crop burning were recorded at the fag end of September around Amritsar. The red dots on the map over Punjab progressively increases as October starts.  By the third and fourth week of October and leading well into November, the map of Punjab and some parts of Haryana is littered with hundreds of red dots reflecting the instances of crop burning.

Instances of crop burning over Punjab and Haryana on October 29, 2017. Source: NASA Worldview

Usually, the effect on Delhi is much more than other cities in the region as Delhi’s air is already highly polluted, thanks to road dust, smoke from garbage-burning and millions of vehicles that ply on its wide roads. Add the PM_2.5 and PM₁₀ pollutants received from adjoining states, a deadly recipe brews in the air of national capital.

Last year, till the first week of November, Haryana government cracked the whip on farmers who continued to defy orders on burning paddy stubble and initiated action against 1406 violators recovering a fine of Rs 13.75 lakh.

Instances of crop burning over Punjab and Haryana on November 5, 2017. This image also shows the smoke building over the region. Compared to the previous image of October 29, the progression of smoke towards Delhi can be seen. Source: NASA Worldview

Despite that, the practice has continued this year causing troubles to the citizens of Delhi. "This becomes critical at this time. It (air quality) is already loaded (with dust), but stubble burning is the trigger. It becomes the main villain," the Delhi High Court said while hearing a PIL.

Delhi Chief Minister Arvind Kejriwal termed Delhi a gas chamber on Monday. "Delhi has become a gas chamber. Every year this happens during this part of the year. We have to find a solution to crop burning in adjoining states," Kejriwal said.

Contrary view

However, a report last month cited IMD officials and said that Delhi chokes on its own and contributes more than the stubble burning in neighbouring states. Central Pollution Control Board (CPCB) member secretary A Sudhakar had reflected that easterly winds from Uttar Pradesh would bring moisture which trapping the pollutants present in the air leading to dense smog.

Even on Monday, the CPCB has said high moisture level in the air has trapped emission from local sources and hanging low over the city in the absence of wind.

"Total calm conditions, marked by the complete absence of wind has led to the situation. The moisture has trapped emissions from ground level sources," Dipankar Saha, CPCB's Air Lab chief, said.