The first of more than 60 flights repatriating thousands of Indians stranded overseas by the coronavirus lockdown is due to set off on Thursday.
Nearly 15,000 Indians are expected to return on special Air India flights from 12 countries over the next week.
Passengers will pay their own fares and be quarantined on return.
Flights from the US and UK were due to arrive back on Thursday, but were delayed as Covid-19 tests on crew were not done in time, local media reported.
Instead, the first flight to return will be from Singapore, due to arrive into Delhi at 11:35 (06:35 GMT) on Friday. It leaves Delhi at 23:15 (18:35 GMT) on Thursday.
India suspended all international travel in March before it went into lockdown to curb Covid-19 infections.
Since then, the country has operated a few flights to bring back Indian citizens. But the latest exercise, which has been dubbed the Vande Bharath (hail India) mission, is the most organised effort so far.
Eventually, about 200,000 Indians will be brought back, report local media.
If successful, this would be India’s biggest evacuation mission since 1990, when it rescued 170,000 civilians from Kuwait during the Gulf War.
Air India, the country’s national airline, will carry out the mission and fly planes to the US, the UK, Saudi Arabia, Singapore, Qatar and Malaysia, among other countries.
The Indian mission in the UAE alone has received 197,000 applications to be repatriated so far.
Most of the flights are expected to land in the southern Indian state of Kerala, from where tens of thousands go to work abroad.