Geological Survey of India (GSI)

GSI is the government’s own geology survey. It began in 1851 and still works under the Ministry of Mines.

1. Who runs GSI, and where is it based?

GSI is an attached office of the Ministry of Mines, and its headquarters are in Kolkata. An attached office carries out the work of a ministry but is not a part of its core secretariat.

GSI has six regional offices. They are in Lucknow, Jaipur, Nagpur, Hyderabad, Shillong and Kolkata. It also has state unit offices in almost every state.

PIB describes GSI as a geoscience organisation of international repute. It also acts as a repository of geoscience information.

2. Why was GSI set up in 1851?

GSI was set up in 1851 mainly to find coal for the railways. Steam trains and steamships needed coal, and India’s coal was poorly known.

The first head was Sir Thomas Oldham, who joined in 1851. His title was Superintendent. Work began in Calcutta, now Kolkata, and the first years went into hunting for coal.

The date matters for exams. Remember the year 1851 and the purpose, which was coal for the railways.

3. How did GSI's job grow beyond coal?

GSI’s job grew because coal cannot be found without a map of the rocks. In 1852 Oldham argued this to the government. He said India’s geological structure had to be mapped first. He then drew up a plan to widen the department’s area of work.

That argument widened the work from coal-hunting to geological mapping. Today GSI creates and updates India’s national geoscience information. It also assesses mineral resources.

The tools now include ground surveys, airborne surveys and marine surveys. GSI also studies glaciers, natural hazards and earthquake zones.

GSI keeps the national map data and studies hazards. Two jobs stand out: sharing data and handling landslides.

4. How does GSI share its maps and data?

GSI shares its data through online portals. The National Geoscience Data Repository (NGDR) is the main one. It is an online platform for finding, sharing and studying geospatial information.

The Ministry of Mines launched the NGDR on 19 December 2023. GSI and the Bhaskaracharya National Institute for Space Applications and Geo-informatics (BISAG-N) built it.

GSI maps are also on its Bhukosh map portal, and landslide maps are on the Bhusanket portal. The Bhooskhalan mobile app shows landslide data too. Free download is open to all users.

5. What is GSI's role in landslide mapping?

GSI is the nodal agency for landslide studies. A nodal agency is the one body that leads a task for the whole country.

Under the National Landslide Susceptibility Mapping (NLSM) programme, GSI has mapped about 4.3 lakh square kilometres. The maps are at a scale of 1:50,000. They cover hilly parts of 19 states and Union Territories. These include the Himalaya, the Tertiary Belt of the North-East and the Western Ghats.

The maps split land into high, moderate and low zones. Planners use them to decide where to build.

GSI also holds records of 91,000 past landslides. Field teams have checked 33,904 of them.

6. How is landslide warning improving?

GSI is moving from broad maps to close-up maps. It now makes meso-scale maps at 1:10,000 and 1:5,000. The target is 200 critical sectors by 2028. By the end of field season 2024-25, 160 were done.

On warnings, GSI worked with the British Geological Survey on the LANDSLIP project. The team built a prototype Landslide Early Warning System (LEWS). It uses rainfall thresholds, which are rainfall levels beyond which slopes become dangerous.

Two pilot areas test it. They are Darjeeling in West Bengal and the Nilgiris in Tamil Nadu. Since the 2020 monsoon GSI has sent daily forecast bulletins there.

7. What does GSI do about glaciers?

GSI studies glaciers but does not run a glacier warning system. It measures mass balance, which is the yearly gain or loss of ice. It also tracks whether selected Himalayan glaciers are retreating or advancing.

For sudden floods, GSI sits in a group set up by the National Disaster Management Authority (NDMA). That group looks at methods to watch for avalanches and Glacial Lake Outburst Floods (GLOFs). A GLOF is a flood that bursts out when a glacier-fed lake breaks its banks.

Critical minerals feed batteries, electronics and clean energy. GSI is the first stage of the hunt.

8. What are critical minerals, and why does GSI lead the search?

Critical minerals are minerals that a country needs but cannot easily source. Lithium, graphite and rare earth elements are examples. Rare earth elements (REEs) are a group of metals used in magnets and electronics.

The Mines and Minerals (Development and Regulation) Act was amended in 2023. It lists the critical and strategic minerals in Part D of its First Schedule. The Centre auctions them.

GSI leads the first stage. It surveys the rocks and finds where the minerals may lie. Auctions and mining follow later.

9. How much exploration has GSI planned?

GSI’s critical mineral work has grown each year. In field season 2023-24, it formulated 115 projects on strategic and critical minerals. Fertilizer minerals were part of that count.

A reply to Parliament in late 2025 gave newer numbers. GSI ran 195 critical mineral projects in 2024-25. It took up 230 in 2025-26.

A field season is the working year in which GSI teams go out to the field.

10. What did the Reasi lithium find actually show?

GSI found lithium in the Salal-Haimana area of Reasi district in Jammu and Kashmir. It was India’s first such lithium estimate. The inferred resource is 5.9 million tonnes. PIB announced it on 9 February 2023.

Inferred means the estimate rests on limited evidence. The code G3 marks an early stage of exploration. So this is not a proven reserve that can be mined today.

GSI handed over this report to the state government. It came with 15 other resource reports and 35 geological memoranda. In all, 51 mineral blocks were handed over in 11 states and Union Territories.

Two changes came within a week in mid-2026. GSI got its first woman leader, and it signed a technology pact.

11. Who is the new Director General?

Varsha Ashok Aglawe became the 54th Director General of GSI. She took charge on 31 July 2026. She is the first woman to lead the organisation. GSI is about 176 years old.

She joined GSI in 1992 after a short time at the Indian Bureau of Mines. Before this post she headed GSI’s Eastern Region in Kolkata. She succeeds Asit Saha, who served from 27 July 2024 to 31 July 2026.

Her field is palaeontology, the study of fossils, and palynology, the study of pollen and spores. Her work covers the K-T boundary and the Gondwana basins of the Satpura region.

12. What does the C-DAC agreement do?

On 4 August 2026, the Centre for Development of Advanced Computing (C-DAC) and GSI signed an umbrella MoU. C-DAC works under the Ministry of Electronics and Information Technology. The signing took place in New Delhi.

The deal joins C-DAC’s High-Performance Computing (HPC) power with GSI’s geological know-how. HPC means very fast computers that handle huge data sets.

Three uses are planned. One is 3D mapping of what lies underground. Another is a domain Large Language Model (LLM) built from decades of old geological records. The third is landslide watch with Synthetic Aperture Radar (SAR) and study of GLOFs.

The MoU also aims to speed up the discovery of critical minerals and rare earth elements.

CDS 2021 linked GSI to earthquake risk. The question gave four towns and asked which one was riskiest.

13. What did CDS-II 2021 ask, and how do you answer it?

The question came in the Combined Defence Services (CDS) II 2021 General Knowledge paper as Q83.

Stem as printed on our CDS-II 2021 paper page. Who amongst the following will be at more risk with respect to the earthquake hazard zone specified by the Geological Survey of India?

The options were (a) Shahji at Secunderabad, (b) Ranbir at Indore, (c) Malti at Pithoragarh and (d) Maitri at Bhubaneswar. The answer is (c).

Pithoragarh lies in the Himalayan belt of Uttarakhand, which is Zone V. The other three towns sit in lower zones, II or III. Look for the Himalayan or Rann of Kutch town when you see such a question.

14. Did a sixth seismic zone ever become official?

No. In November 2025 BIS published a new seismic code with a new top Zone VI. It covered the whole Himalayan belt. In March 2026 BIS withdrew that code, after concerns raised by the housing ministry.

So the 2016 code applies again. It has four zones, II to V. Zone V is the highest.

For the exam, use the four-zone scale. If a question names Zone VI, read it closely.