As per a new study conducted by 6 Indian scientists, there has been a note steady decline in the sunshine hours in India over the period of last 3 decades. Sunshine hours refers to the period of time of direct sunlight reaching Earth’s surface.
Give Me Some Sunshine — The Golden Bird Says
Researchers studied that data from 20 weather stations between 1988 and 2018 and observed that only the northeast saw brief seasonal reprieves.
The study, published in Scientific Reports (Nature Portfolio), attributes the decline in sunshine hours to increasing cloud cover, aerosols, and local weather changes.
Speaking of the areas that observed sharpest annual reductions, then these include the northern inland areas such as Amritsar and Kolkata, along the Himalayan belt, and on the west coast near Mumbai.
As per the study, all of India’s 9 geographical regions have noted decline in the same, though at varying rates. Monthly data revealed higher sunshine hours from October to May but steep drops from June to July—reflecting the influence of monsoon clouds.
This trend of declining sunshine is also tied to India’s long standing long-standing air pollution crisis, among the world’s worst since the 1990s.
Rapid urbanisation, industrial growth, and land-use changes have intensified fossil fuel use, vehicle emissions, and biomass burning—producing aerosols that scatter sunlight and cool the surface.
In the winters, factors like smog, crop burning and temperature inversions across the Indo-Gangetic plains create and suspend light-scattering particles in the atmosphere that eventually reduce sunshine significantly.
As per Manoj Kumar Srivastava, Professor in Banaras Hindu University, aerosols indirectly foster clouds that linger longer without rain, further blocking sunlight.
Another expert of this subject, an Atmospheric scientist Sachchida Nand Tripathi of IIT Kanpur estimates aerosols have cut India’s sunlight by 13%, while clouds caused an additional 31–44% decline in surface solar radiation from 1993 to 2022.
Why to Bat an Eye?
The gradual and ultimately decline in the sunshine hours can threaten the agriculture, daily life as well as the country’s solar ambitions.
With over 100 GW installed and a 2030 target of going till 500 GW, solar currently represents 47% of India’s renewable energy capacity, the lack of sunshine could be a big blow.
In addition, the current pollution already decreases the photovoltaic efficiency by 12–41%, costing up to $835 million in lost generation annually. Cleaner air could increase solar output by 6–28 terawatt hours per year—enough to power millions of homes. Pollution also slashes crop yields, particularly rice and wheat, by 36–50% in India’s most polluted regions.
Globally, similar patterns have been observed. Europe and China both experienced “global dimming” due to industrial emissions, followed by partial recovery—or “brightening”—after stricter clean-air measures in the 1990s. While satellite data shows global sunlight increasing since the 1980s, India’s persistent pollution means the nation risks missing out on this brightening—its future energy and food security clouded by its own smog.
Summary
A study conducted by 6 Indian scientists reveals a steady decline in sunshine hours across India over the last 30 years, driven by increasing clouds, aerosols, and pollution. This reduction threatens agriculture, daily life, and solar energy goals, with pollution cutting solar efficiency by up to 41%. While global sunlight is rising, India’s persistent smog risks dimming its energy and food security prospects.
