Revised length of India’s coastline, Government of India circular dated 29th April 2025

MR-1401111/2024-TRW (S)
Government of India
Ministry of Ports, Shipping and Waterways
Transport Research Wing

Room No. 102A, IDA Building
Jamnagar House, New Delhi- 1100 I I
Dated: 29th April, 2025

CIRCULAR

Change in length of coastline of India -reg

Reference is invited to the report of Survey of India, Department of Science and Technology (copy enclosed) vide which it is to inform that due to change in methodology of calculation, the length of India’s coastline has been recalculated and is now 11098.81 kms.

Background Note

1. The ‘Length of Coastline of India’ as per MHA website is 7516.60 Km since the 1970s and different govt departments have been using different figures for the coastline. The issue was examined at BM-li Division. Department of Border Management. Ministry of Home Affairs, New Delhi in 2019 wherein it was learnt that Coastal Protection and Development Advisory Committee (CPDAC) has been deliberating on this issue since its 11th meeting in 2010. In its 16th meeting held on 16-7-2019, CPDAC accepted the new ‘Length of Coastline of India’ computed by National Hydrographic Organisation (NHO), Dehra Dun as 11,084.50 Km along with the methodology for its computation. This new ‘Length of Coastline of India’ had the concurrence of all Coastal Stales and UTs. Ministry of Home Affairs (Department of Border Management) BM-II Division, New Delhi requested Survey of India (Sol) to publish notification in this regard. Solobserved certain deviations in this ‘Length of Coastline of India’ w.r.t to the accepted methodology and requested to finalise the Terms of Reference (ToR) for Standardisation of Maritime Parameters.

2. Updated ToR were finalized at National Security Council Secretariat (NSCS), New Delhi on 10-08-2023 which were unanimously accepted from stakeholders across different central & state government department and ministries viz. Indian Coast Guard, Ministry of Home Affairs. Ministry of External Affairs, Ministry of Environment Forest & Climate Change, Ministry of Earth Sciences, Ministry of Jal Shakti. National Hydrographic Organisation, National Remote Sensing Centre, Survey of India. Salient Terms of Reference (ToR) for measuring Re-verified Length of Coastline of India (11,098.81 kms) are as mentioned below:

a. The length of coastline has been measured at the High-Water Line with base data of 2011 on Electronic Navigation Charts (ENCs) prepared by the National Hydrographic Office (NHO).

b. The datum and projection for the coastline length is WGS-84 and respective UTM Zones.

c. The scale has been generalised to I:250,000 or lesser using ENCs of NHO

d. Mouth of the rivers. creeks, estuaries, backwaters. etc. have been closed at suitable places by NHO and only segment of length closing of river mouth has been considered.

e. The length of coastline of islands which get connected to mainland during low tide conditions has also been added in the length of coastline.

f. The’ Length of Coastline of India’ will be reviewed in a cycle of 10 years with newer data sets.

3. The length of the coastline was re-assessed as 11,098.81 kms by NHO in coordination with Sol as per the latest terms of references. Representatives of the coastal States/UTs and other stakeholders deliberated on the re-verified coastline length during the discussion in the meeting dated 04-01-2024 at National Security Council Secretariat (NSCS), New Delhi. CPDAC accepted the revised coastline length of India after obtaining concurrence from all coastal States/UTs.

4. As discussed during the meeting held on 17-09-2024 under the Chairmanship of the Surveyor General of India, it was decided that the probable reasons for the variation between the existing coastline length i.e. 7516.6 kms as per the records of the Ministry of Home Affairs (MHA) and the re-verified coastline length i.e. 11098.81 kms must be outlined prior to the publication of the updated length. This was unanimously endorsed by all stakeholders participating in the meeting.

5. The main reason for the deviation in the existing coastline length of 7516.6 kms as per MHA records and the re-verified coastline length of 11098.81 kms is due to the probable variation in scale and calculation methods. The length of coastline calculated in 1970s might have been computed from the then available records at the scale of I:4,500,000 or smaller whereas the re-verified data has been computed at the scale of I:250,000. It is understood that the length of coastline is liable to vary when it is measured from maps of different scales. The larger the scale of map greater may be the outcome of the length. This is because larger scale data capture more intricate details like bays, inlets, and minor irregularities that are smoothed out at smaller scale data. Further conventional/manual methods might have been used for the computation of the 1970 data whereas modem GIS software have been used for the computation of the re-verified data. The no. of offshore islands/islets of India are finalised as 1298 Offshore islands/islets (1059 islands and 239 islets) in the reconciliation exercise of the offshore islands of India. Secondly the length of offshore islands has been added in the total length of there-verified coastline which might have been left out in the 1970s coastline length due to scale constraint and conventional/ manual measuring methods. Further, peripheral coastline(High-Water Line) of individual offshore islands has been used for the calculation of coastline length.

Length of Coastline of India

The State-wise/UT-wise ‘Length of Coastline of India’ arehereby mentioned below: