Archive · 10 Aug 2026
Unusually High Ozone over Bay of Bengal Explained by Scientists
The Earth has a special layer in the sky called the ozone layer.
It acts like a big umbrella that blocks the Sun's harmful rays and keeps us safe.
Normally, this layer is found very high up, about 25 to 30 kilometers above the ground.
Scientists noticed that over the Bay of Bengal, a big patch of ocean near India, there was an extra thick layer lower than usual, at 21 to 23 kilometers.
There was much more ozone there than usual, and it stayed for more than a day.
Scientists wanted to know how it got there.
They used special radars, weather balloons, and satellites to look closely.
They found that air full of ozone was pushed into the area, moved downward, and got squeezed together.
This is important because understanding the ozone layer helps us protect life on Earth from the Sun's harmful rays.
Scientists found an unusually thick ozone layer at 21–23 km altitude over the North Bay of Bengal, lower than the typical 25–30 km range.
Ozone levels were much higher than normally observed over eastern India and persisted for more than a day.
The finding came from the Phase-I NetRAD-ASMA campaign and was published in Earth and Space Science by the American Geophysical Union.
Researchers combined data from atmospheric radars, weather balloons, satellites (Aura MLS, INSAT-3DR) and advanced atmospheric models.
The ozone build-up was mainly caused by ozone-rich air being transported into the region, followed by downward movement and compression of the air mass.
Sunlight-driven photochemical reactions were ruled out because the enhanced ozone layer was observed during both daytime and nighttime.
- Who
- Researchers from Indian institutions including the Aryabhatta Research Institute of Observational Sciences (ARIES), among them Dr Manish Naja and Dr Samaresh Bhattacharjee.
- What
- Scientists discovered and explained an unusually thick ozone layer at a lower-than-normal altitude over the North Bay of Bengal.
- When
- During the Phase-I NetRAD-ASMA campaign, covering winter conditions over India's subtropical region.
- Where
- Over the North Bay of Bengal, in India's subtropical region.
- Why
- Stratospheric ozone absorbs harmful ultraviolet radiation from the Sun and protects life on Earth, so understanding how ozone moves over the Indian region is important.
- Normal ozone altitude
- 25–30 km
- Observed ozone altitude
- 21–23 km
- Location
- North Bay of Bengal
- Duration of anomaly
- More than a day
- Publication
- Earth and Space Science (American Geophysical Union)
- Research campaign
- Phase-I NetRAD-ASMA
- Main cause
- Transport of ozone-rich air, downward movement and compression of the air mass
- Key instruments
- 206.5 MHz Stratosphere-Troposphere Radar at ARIES Nainital, radars at Haringhata, Gadanki and Kochi, weather balloons, Aura MLS and INSAT-3DR