India won a record ninth Test series in succession Wednesday after drawing the pollution-tainted third and final Test with Sri Lanka in New Delhi.
Top-ranked India won the series 1-0 to equal Australia's record of nine successive Test series victories, between 2005-2008.
The first Test between India and Sri Lanka in Kolkata had ended in a draw and the hosts won the second game by an innings and 239 runs.
But Sri Lanka salvaged some pride in the final match thanks to Dhananjaya de Silva and Roshen Silva, who defied the odds and held out for a draw.
The Test at the Feroz Shah Kotla ground was marred by severe pollution, with fast bowlers from both sides vomiting Tuesday amid thick smog.
In an unprecedented move, Sri Lankan players wore facemasks while fielding to combat the toxic air, which interrupted play on day two as the visitors protested the choking conditions.
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"It was a tough time. The thing is, in Sri Lanka we are not used that, so that's why we struggled (on) the first two days," said Sri Lankan captain Dinesh Chandimal.
"But after that we needed to continue the game. We told the boys we have to forget about that and we need to play the game.
"Today is a fantastic day. It feels like Sri Lanka," quipped the captain, referring to the less smoggy weather Wednesday.
The US embassy website on Wednesday showed concentrations of the smallest and most harmful airborne pollutants hit 234, better than a day earlier but still nearly nine times the World Health Organization's safe limit.
The Board of Control for Cricket in India has said Delhi could be dropped as a venue during winter when pollution spikes.
Dhananjaya, who retired hurt on 119 due to muscle stiffness, and Roshen (74 not out) held Sri Lanka steady over three sessions of play on the final day, after the visitors were set a huge 410 victory target late on day four.
Roshen was batting alongside Niroshan Dickwella on 44 when the two teams decided to shake hands with just seven mandatory overs left for the day.
Spinner Ravindra Jadeja rattled the Sri Lankan top order with three strikes, including Angelo Mathews' key wicket in the morning session.
But De Silva thwarted a persistent Indian attack with his third Test hundred.
He built crucial partnerships with Chandimal (36) and then with Silva, who had begun his Test career with a duck in the first innings.
Silva also combined with Dickwella in an unbeaten 94-run stand.
Indian skipper Virat Kohli praised the Sri Lankan batsman for digging their heels in on a wearing pitch.
"Always when you're not able to finish the game off in the second innings, especially when you had them three down yesterday, feels a bit of (a) disappointment, but I wouldn't say it's a very bad feeling," he said.
"They played well, firstly, credit to them. They really stuck it out. Their batsmen really applied themselves, showed composure and confidence and didn't give our bowlers anything throughout the day."
Kohli was named man of the series for his prolific performances including two double centuries.