Indians struggled to pay for basics goods like food and fuel today and wondered how to get hold of their cash, after India suddenly withdrew 500 and 1,000 rupee notes from circulation in a bid to flush out money hidden from the tax man.
The shock measure also sent shudders through the investment community on a day when the markets were reeling at Republican candidate Donald Trump winning the US election.
India's National Stock Exchange share index slumped as much as 6.3% in early trade before recovering some of the losses in later trade.
The currency move, announced yesterday by Prime Minister Narendra Modi, aims to bring billions of dollars worth of unaccounted wealth into the mainstream economy and curb corruption.
It was also designed to stop anti-India militants suspected of using fake 500 rupee notes to fund operations.
From midnight, the larger banknotes ceased to be legal tender for transactions other than exchanging them at banks for smaller notes.
Retailers refused to accept the bills, worth around $7.50 and $15 respectively, and people were unable to access ATMs after banks closed them down.
To be effective the move had to be unexpected, analysts said.
But it was also fraught with problems for an economy largely fuelled by cash, especially for India's poorest citizens, many of whom work in the large rural economy.
India's "black economy," a term widely used to describe transactions that take place outside formal channels, amounted to around 20% of gross domestic product, according to investment firm Ambit.
New bills, of 500 and 2,000 rupees, will be introduced from November 10.
The extent of the impact of the measures became evident as petrol stations and hospitals also refused to accept larger denomination banknotes, even though the government had given them a waiver to continue accepting them.
Meanwhile, bank ATMs were closed and banks prepared for the flood of people seeking to exchange larger banknotes for smaller ones.
Modi's move to go after hidden assets also threatens to derail politicians' election plans ahead of state polls including the key battleground of Uttar Pradesh early next year.
With no state financing, India's elections run on resources that candidates generate themselves, most of it in cash.
The main opposition Congress party said it supported moves to attack the black economy, but that withdrawing bigger denomination notes would hit the common man first.
"Ordinary Indians will suffer - families saving for weddings, the small traders and businessmen," said Randeep Singh Surjewala, the party spokesman.
In the stock market, real estate firms that depend on cash transactions were hit particularly hard, with DLF Ltd, India's biggest property developer, down more than 20%.
But analysts said the move would prove beneficial to India in the longer term, by ushering in transparency and bringing transactions into the formal economy, and providing additional revenue for a country that has long struggled to contain its fiscal deficits.
It could also lead to easing inflation, raising the prospect of additional rate cuts from the central bank, which lowered the key repo rate by 25 basis points last month.
