According to new analysis led by researchers at Stanford University within the US, coal-fired power crops are quietly depleting India’s rice and wheat output, destroying up to 10% of the yield in a number of states.
The emissions from coal power crops embrace carbon dioxide, nitrogen oxides, sulphur oxides, fly ash, soot, suspended particulate matter, and different hint gases. These pollution have been linked to smog, acid rain, eutrophication and numerous different environmental burdens.
An elusive hyperlink
In the brand new examine, PhD scholar Kirat Singh and his colleagues turned the highlight on the much less explored penalties of nitrogen dioxide (NO2) on crop productiveness.
The nitrogen oxides basically are a longtime facet impact of India’s coal dependence. They are phytotoxic, which means they stress crops, and have been identified to hinder mobile perform and intrude with essential enzymatic actions. The oxides additionally contribute to the formation of ozone, which in flip exacerbates crop harm and produces particulate matter that limits the quantity of daylight accessible for photosynthesis.
“We know that coal-fired power plants contribute significantly to air pollution,” Singh stated. “And we also know from past studies that various pollutants, including NO2, can negatively impact crop growth. But there hadn’t been a study linking the two in a systematic way at the power-plant level, particularly in India.”
Tracking plant well being
To compensate for the dearth of floor monitoring stations in agricultural areas, the researchers used information from satellite tv for pc pictures to glean high-resolution insights into NO2 focus throughout India. Since a number of power crops contribute to NO2 air pollution throughout completely different distances, the researchers summed up all coal-attributable NO2 emissions reaching every location as an alternative of isolating particular person sources. This method gave them a complete image of the quantity of air pollution to which agricultural areas have been uncovered.
Then, to estimate how NO2 from coal-fired power crops affected crop yield, the researchers turned to a satellite-derived vegetation index. They used a bodily sign referred to as near-infrared reflectance of vegetation (NIRv) as a proxy for plant well being. NIRv measures greenness. Healthy crops are richer in chlorophyll, which might’t be detected by seen mild however is delicate to near-infrared mild. So a better share of near-infrared mild is mirrored by leaves in wholesome crops.
Using pre-established coefficients, the researchers might hyperlink NO2 ranges, measured by the TROPOMI satellite tv for pc, to adjustments in NIRv. They used India-specific coefficients of 0.0006 for monsoon rice and 0.0007 for winter wheat. For each 1 mol/m2 enhance in NO2, for instance, the corresponding drop in NIRv was 0.0006 and 0.0007, respectively.
Prior analysis has already proven a linear relationship between NIRv and crop yield, permitting the researchers to immediately estimate how a lot yield was misplaced due to air pollution. They set a baseline NIRv of 0.007, representing zero crop development, and calculated the proportion lower in yield based mostly on pollution-driven declines in greenness. This technique helped them quantify the agricultural harm wrought by NO2 with out requiring bodily discipline measurements.
Blowin’ within the wind
They additionally analysed wind patterns to differentiate between air pollution from coal crops from that from different industrial and environmental sources. This step helped the staff unravel main variations within the results of coal air pollution throughout States.
For instance, Chhattisgarh, a significant hub for coal-fired power, had the best share of NO2 air pollution from coal crops: about 19% of NO2 detected within the monsoon season and 12.5% in winter got here from coal crops.
Surprisingly, Uttar Pradesh had excessive general NO2 ranges however solely a small portion of that got here from coal power, whereas Tamil Nadu had comparatively low NO2 air pollution however the bulk of it got here from coal power.
Coal’s contribution to air air pollution thus assorted by area. Not all power crops have the identical affect: these situated close to fertile farmland with a excessive emissions publicity brought on essentially the most agricultural harm, Singh stated.
An ignored loss
Crop harm depth — measured as monetised loss per gigawatt-hour (GWh) of electrical energy generated — for wheat and rice touched up to $17,370/GWh (Rs 15 lakh on February 6, 2025) and $13,420/GWh (Rs 11.7 lakh) respectively.
About 20% of coal-fired electrical energy technology through the monsoon season accounted for half of all coal NO2-related rice losses whereas 12% of whole winter season technology was linked to 50% of wheat losses.
This instructed that concentrating on a comparatively small subset of extremely polluting power stations might nonetheless have important advantages for agricultural productiveness. To wit, as per the examine, the yield of 5.7% of cropland in West Bengal close to coal-fired power stations might enhance 5-10% whereas the positive aspects of 1.66% might exceed 10%. Similarly in Madhya Pradesh, the yield in 5.9% of cropland might enhance 5-10% yield positive aspects and one other 11.9% might achieve by greater than 10%.
To evaluate, the annual yield development for kharif rice and rabi wheat has averaged simply 1.7% and 1.5% respectively between 2011 to 2020.
According to the examine, India’s rice manufacturing might achieve $420 million a 12 months and wheat $400 million a 12 months, roughly Rs 7,000 crore in whole.
Expected yield positive aspects from eliminating coal-attributable nitrogen dioxide concentrations in main rice- and wheat-producing states. Large tracts of cropland in all key states are anticipated to see yield enhancements of 1% from eliminating coal-related NO2. Data from 2019 rising seasons.
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India and coal
As the 2025-2026 Economic Survey in addition to power consultants have famous, coal power performs an important function in India’s development in the mean time. The 2025-2026 Union Budget has allotted 255% extra for the Ministry of Coal over revised estimates of FY 2024-2025.
India’s demand for meals is hovering as effectively. In 2024, the Global Hunger Index ranked India one hundred and fifth out of 127 nations on meals safety. Rice and wheat are staple crops in India and in lots of elements of the world to which these grains are exported.
Singh stated he hopes to inform coverage reforms that may permit the coal and agricultural sectors to meet within the center. “When you’re crafting policy around controlling pollution from the power sector, considering crop impacts alongside health and greenhouse gas emissions can help policymakers prioritise where that pollution control equipment should be installed,” he stated.
“If you want to optimise the money that is being invested in installing all of this pollution-control equipment, you want to focus on power plants where it would bring the most benefit. Policymakers might find information in our research that could be helpful in terms of figuring out which power stations to prioritise,” he added.
Singh grew up in New Delhi and stated its poor air high quality motivated him to examine the results of air air pollution on human in addition to crop well being. In future, Singh is planning to additional examine how coal power crops have an effect on agriculture at massive in India, together with the consequences of different pollution on crop productiveness.
Ashmita Gupta is a science author.
Published – February 27, 2025 05:30 am IST
