He is best remembered for the Mahalanobis distance, a statistical measure, and for being one of the members of the first Planning Commission of free India.

Mahalanobis belonged to a prominent Bengali Brahmin family of landed gentry in Bikrampur, Dhaka, Bengal Presidency (now in Bangladesh).

Gurucharan was actively involved in social movements such as the Brahmo Samaj, acting as its treasurer and president.

Born in the house at 210 Cornwallis Street, Mahalanobis grew up in a socially active family surrounded by intellectuals and reformers.

[2] In Calcutta, Mahalanobis met Nirmalkumari (Rani), daughter of Heramba Chandra Maitra, a leading educationist and member of the Brahmo Samaj.

He was concerned about Mahalanobis's opposition to various clauses in the membership of the student wing of the Brahmo Samaj, including prohibitions against members' drinking alcohol and smoking.

Sir Nilratan Sircar, P. C. Mahalanobis' maternal uncle, took part in the wedding ceremony in place of the father of the bride.

The institute also gained major assistance through Pitambar Pant, who was a secretary to Prime Minister Jawaharlal Nehru.

As Nobel Prize-winning economist Angus Deaton and co-author Valerie Kozel wrote in 2005: "Where Mahalanobis and India led, the rest of the world has followed, so that today, most countries have a recent household income or expenditure survey.

Economists TN Srinivasan, Rohini Somanathan, Pranab Bardhan and another Nobel-winner Abhijit Banerjee have since argued that there is "no other instance of an entirely homegrown institution in a developing country becoming a world leader in a large field of general interest".

[15] Mahalanobis distance is one of the most widely used metrics to find how much a point diverges from a distribution, based on measurements in multiple dimensions.

He used the data collected by Annandale and the caste-specific measurements made by Herbert Risley to come up with the conclusion that the sample represented a mix of Europeans mainly with people from Bengal and Punjab but not with those from the Northwest Frontier Provinces or from Chhota Nagpur.

Early surveys began between 1937 and 1944 and included topics such as consumer expenditure, tea-drinking habits, public opinion, crop acreage and plant disease.

Harold Hotelling wrote: "No technique of random sample has, so far as I can find, been developed in the United States or elsewhere, which can compare in accuracy with that described by Professor Mahalanobis" and Sir R. A. Fisher commented that "The ISI has taken the lead in the original development of the technique of sample surveys, the most potent fact-finding process available to the administration".

[25] Mahalanobis also had an abiding interest in cultural pursuits and served as secretary to Rabindranath Tagore (about whom he would write in the Journal of the Oriental Society of Australia), particularly during the latter's foreign travels, and also worked at his Visva-Bharati University, for some time.

[27][28] On the occasion of his 125th birth anniversary on 29 June 2018, Indian Vice-President M Venkaiah Naidu released a commemorative coin at a programme at ISI, Kolkata.