Air pollution biggest threat to agriculture, says study

Air pollution poses the biggest threat to India's agriculture production as it could lead to a decline of more than 30 per cent in grain yields in many northern states.

Using historical data and statistical tools, two researchers showed that in Uttar Pradesh, wheat yields are almost 50 per cent lower than what could have been if there was no air pollution.

Uttar Pradesh is not only India's most populous state, but it is also the largest producer of both wheat and rice in the country, providing over one-third of India’s wheat and 14 per cent of India’s rice.

 Almost two-thirds of the potential crop loss in Uttar Pradesh is due to rising pollution level.

The adverse impact is also seen in Uttarakhand, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhattishgarh and West Bengal.

 The bread basket of Punjab and Haryana as well as less polluted southern states like Tamil Nadu and Andhra Pradesh, however, are less affected.

“What our study did was to use historical data and a statistical approach, as opposed to models, to understand how pollutants, temperature and precipitation and technology trends have all contribute together to Indian crop yields over time. We find over the past three decades, pollution has been dragging yields down in India in a major way,” Jennifer Burney, one of the co-authors of the study and a scientist at the University of California, San Diego told Deccan Herald.

This is the first research to demonstrate how air pollution contributes more on the crop loss than the climate change consequences. Crop yield data between 1980 and 2010 was used to validate the statistical models.

“Averaged over India, yields in 2010 were up to 36 per cent lower for wheat than they otherwise would have been, in the absence of climate and pollutant emissions trends, with some densely populated states experiencing 50 per cent relative yield losses,” the researchers reported in the Proceedings of National Academy of Sciences.

The estimates for rice – average reduction of about 20 per cent — too are large but not statistically significant.

What is more important is the fact that an overwhelming fraction (almost 90 per cent) of these losses is due to the direct effects of air pollution caused by dust and soot particles. “Agronomically, wheat is more sensitive to ozone than rice. Also, pollutant levels are higher in the wheat (rabi) season than the kharif season,” she said.