Aiken, who began the last round with a three-stroke lead, scored a flawless five-under 67 and sealed his second win on the European Tour with a birdie at the 18th hole on Sunday.
The 29-year-old from Johannesburg finished with an overall score of 23-under 265, three shots ahead of local boy Gaganjeet Bhullar at the Greg Norman-designed par-72 Jaypee Greens outside New Delhi.
Aiken, who won the Open de Espana in 2011, earned €300 000 (approximately $392 000) for his efforts that followed compatriot Jbe Kruger's triumph in the Avantha Masters last year.
Bhullar, who was six shots behind the leader at the start, fired an eight-under 64 to come in at 268, ending his campaign with three birdies in the last five holes to keep the pressure on Aiken.
Bhullar finished two strokes ahead of third-placed Liang Wenchong of China, who had overcome a double-bogey on the sixth with a spectacular hole-in-one on the par-three seventh.
"It's a big relief to win because the others played unbelievable golf," said Aiken.
"There was no breathing space the whole day with Gaganjeet having so many birdies towards the end.
"It was no walk in the park, but I think I played the par-fives well. This has been a fantastic week in India and ended just the way I wanted it to."
Aiken was the sixth South African to win a European tour events this year following the success of Charl Schwartzel at the Alfred Dunhill championships, Louis Oosthuizen (Volvo Golf Champions), Richard Sterne (Johannesburg Open), Darren Fichardt (Africa Open) and Dawie Van der Walt (Tshwane Open).
Bhullar, cheered on by some 500 Indian fans, birdied the first three holes, had an eagle on the fifth before a spectacular finish saw him birdie three of the last five holes.
"After a few weeks, no one will remember that I came second. Everyone will only talk of Thomas," said the 24-year-old.
"But the important thing is that my game has improved.
"This tournament was like a putting competition. Everyone was hitting the ball long, it all depended on how you putted. I thought Thomas would make a mistake somewhere, but he played solidly the last two days."
Kiradech Aphibarnrat of Thailand, who was in the last group with Aiken and Liang, finished fourth on 271. India's richest golf event was co-sanctioned by the European and Asian Tours. – AFP