India won a record ninth Test series in succession on Wednesday after drawing with Sri Lanka in the pollution-tainted third and final Test in New Delhi.
Top-ranked India won the series 1-0 to equal Australia's record of nine successive Test series victories, between 2005 and 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.
Sri Lanka managed to salvage some pride in the in final match thanks to Dhananjaya de Silva and Roshen Silva, who defied the odds and fought back to deny India a win.
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 being set 410 for victory 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.
The Test was marred by severe pollution in the Indian capital, with fast bowlers from both sides vomiting on Tuesday.
In an unprecedented move, Sri Lankan players wore face masks while fielding to combat the toxic air, which interrupted play on day two.
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 Organisation's safe limit.
On the field, it was Ravindra Jadeja who rattled the Sri Lankan top order with three strikes including Angelo Mathews' key wicket in the morning session. But De Silva thwarted the Indian attack with his third Test hundred.
He built crucial partnerships with skipper Dinesh Chandimal (36) and then with Silva, who began his Test career with a duck in the first innings.
Silva also combined with Dickwella in an unbeaten 94-run stand.