An estimated 17 million Indians were living abroad in 2017, making India the largest source country for international migrants globally, up from seven million in 1990 and a 143 per cent increase, according to an IndiaSpend analysis of data from the United Nations Department of Economic Affairs.

Over the same period, India's per capita income increased by 522 per cent (from $1,134 to $7,055), providing more people the means to travel abroad in search of employment opportunities they were not finding at home.

At the same time, the number of unskilled migrants leaving the country has been falling: An estimated 391,000 left India in 2017, almost half the number in 2011 (637,000), according to a new report by the Asian Development Bank (ADB). However, this does not necessarily mean that an increasing proportion of India's emigrants are likely to be higher skilled or that policymakers should be worried about a rise in "brain drain".

The above figures refer to unskilled migrants travelling on Emigration Check Required (ECR) passports—passports issued by the Ministry of Overseas Indian Affairs to those leaving for employment in certain countries in the Middle East and Southeast Asia. Changes in the government criteria used to class workers as unskilled, leading to more migrants travelling on non-ECR passports, could be part of the reason for the declining trend.