PIB TrackerAn ozone layer where it should not be, 22 km over the Bay
Indian radars, balloons and satellites caught an unusually thick ozone layer at 21–23 km over the North Bay of Bengal — well below the usual 25–30 km peak — and traced it to sinking, compressing air rather than sunlight.
What happened
- An unusually thick ozone layer was found at about 21–23 km over the North Bay of Bengal.
- Ozone normally peaks at about 25–30 km, so this sat well below the usual maximum.
- It persisted more than a day and appeared day and night, ruling out photochemistry as the main cause.
- Radars found persistent downward air motion in the lower stratosphere.
- The cause was transport of ozone-rich air followed by descent and compression.
For Prelims
- The ozone layer: in the stratosphere, absorbing harmful ultraviolet radiation; normal peak 25–30 km.
- The anomaly: an enhanced layer at 21–23 km over the North Bay of Bengal, lasting over a day.
- ARIES: the Aryabhatta Research Institute of Observational Sciences, Nainital — an autonomous institute under the DST.
- ST Radar: the indigenously developed 206.5 MHz Stratosphere–Troposphere radar; companion radars at Haringhata, Gadanki and Kochi.
- Satellites used: Aura MLS (NASA) and INSAT-3DR.
- NetRAD-ASMA: the Phase-I nationwide atmospheric campaign under which the study was carried out.
- Note: stratospheric ozone is protective; tropospheric ozone at the surface is a pollutant and a greenhouse gas.
For UPSC: A precise atmospheric-science card that is not about the ozone hole. Use it for stratospheric dynamics and ozone transport, indigenous observation infrastructure, and the difference between protective stratospheric and harmful tropospheric ozone.
What it is NOT: This is a dynamical redistribution of existing ozone, not ozone creation or depletion — it says nothing about the ozone hole or the Montreal Protocol, and an enhancement is not a hazard.
For Mains
Syllabus: GS1.10 · GS3.14 · Linkage L2
Anchor
The atmosphere moves ozone around as much as it makes it — and India now has the instruments to watch it happen.
Substantiation (data)
An enhanced layer at 21–23 km against a normal 25–30 km peak, persisting over a day, with persistent downward motion measured by radar.
Exemplification
Four ST radars, ozone balloons, Aura MLS and INSAT-3DR combined to separate transport from photochemistry — the night-time signal being the decisive clue.
Problematisation
Coordinated campaigns like this are episodic; continuous ozone profiling over the Indian region remains sparse compared with the mid-latitudes.
Way-forward
Sustain the national radar-and-balloon network as a standing observation system and feed it into monsoon and climate models.
Position
Indigenous instruments matter most where global datasets are thinnest — and the Indian subtropics are exactly that gap.
Deploys into: Physical geography + atmospheric science (GS1.10, GS3.14) · stratospheric dynamics and ozone transport, indigenous observation infrastructure, and stratospheric versus tropospheric ozone.
Ministry of Science & Technology · 2026-08-10 · PRID 2297177 · PIB source ↗