This was the queue at half-past-nine this morning - thirty minutes before opening time - outside the Chennai offices of the Reserve Bank of India, the county's central bank. Several hundred people were waiting patiently in stifling temperatures clutching bags full of worthless pieces of paper.
Back in November, the government ordered the just-about-immediate cancellation of 86% by value of all the bank notes in circulation. Notes for 500 Rupees (£6.25) and 1,000 Rupees (£12.50) were declared invalid - and new notes of 500 and 2,000 Rupees issued in their place,
The boldness of the move - intended to drive out 'black' and counterfeit money and boost cashless transactions - was matched by the clumsiness of its execution.
There was a very brief window in which people could take the old notes to a bank and exchange for the new notes ... in theory. Initially there was nowhere near enough of the new notes to meet demand. It was all a bit of a mess. Economic activity flattened - hundreds of millions of Indians were hugely inconvenienced - but the recent state elections have shown that 'demonetisation' has done the BJP government no political harm.
But if you are an Indian living abroad, or were travelling when the high denomination notes were consigned to the rubbish bin, you may well still have a lot of old notes which no one will accept. The RBI is now redeeming the invalid notes of those outside India late last years and so unable to exchange them - and that's what's drawn the crowds on a sweltering March morning.
There was not much shade or water for those in line beyond what they brought with them. Nevertheless the mood was stoic - buoyant even. This group below had already been waiting an hour by the time I came across them, it was another half-hour before the office opened, and my guess is they would be lucky to emerge with their new notes before lunchtime.
How much were they changing? Only one volunteered a figure: 10,000 Rupees (£125) ... so not the sort of sum that anyone wants to write off.
Fifty yards or so away at the end of the queue, people were still falling into line. But I wasn't at all sure that they would make it to the counter by the time the office was due to close - at 2:30pm.