"I was all of five, but I can never forget the night... Hooligans gathered outside our house, and the horror we felt," he says.
The date was October 31, 1984. In the afternoon, then Prime Minister Indira Gandhi had been assassinated by her two Sikh bodyguards. Within hours, reprisals had started across the country against the Sikhs.
Mr Singh's father ran a book shop in Rourkela, an industrial city located in Odisha. But the shop was burnt to the ground and the family was forced to move to the nearest relief camp, hastily erected in the dead of the night.
Finding their feet in Rourkela looked tough and the family moved to Delhi, hoping for a fresh start.
In 1997, he failed to join IIT -- his dream institution -- despite cracking the entrance exam in his first attempt. He took the exam again and had to fund the course by giving tuitions.
Between 2002 and 2009, he changed four jobs - including at Intel and Freescale semiconductor -- before he met Upasana Taku. Now his wife and Mobikwik co-founder, Ms Taku then had just returned to India after a stint at Paypal in the US.
While his family wasn't very supportive of his start-up idea, which meant quitting a cushy job, the couple was convinced about the possibilities of the virtual wallet market.
Today, Mobikwik claims to have 25 million users and is aiming to touch 150 million and $5 billion in payments.
Competition from bigger players like Paytm is intense. But Mr Singh's parting shot was, "We have grown threefold since last year and soon we'll get there too."
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