Sri Lanka coach Nic Pothas praised his team's perseverance on Tuesday against a formidable India despite severe pollution which made players from both sides vomit during the third Test in smog-bound New Delhi.

Fast bowlers Suranga Lakmal and Mohammed Shami threw up as pollution levels soared at the Feroz Shah Kotla stadium, and Sri Lankan fielders again turned to face masks to combat the foul air.

Sri Lanka were reeling on 31-3 at stumps, chasing a daunting 410-run victory target.

Dhanajaya de Silva on 13 and Angelo Mathews were batting when bad light stopped play on the fourth day.

Pothas told reporters his men played “brilliantly” despite being ill from the smog, which hit levels 15 times the World Health Organisation's safe limit.

“I thought the guys did superbly well, great attitude. We are professionals and said, 'That situation is a situation, let's get on with it',” Pothas said.

“Our people in discomfort, I think it speaks for itself. The rest we cannot control. The guys did brilliantly today,” the South African added.

Left-arm spinner Ravindra Jadeja struck twice in an over to rattle the visitors, who must bat out three more sessions to save the match and draw the series against top-ranked India .

Shami dismissed opener Sadeera Samarawickrama off a roaring bouncer but stopped in mid-over to vomit, crouching down and then gulping water.

He went on to complete the over but left the field after umpires thought it inadvisable to have a pacer bowling in poor light.

“Not ideal to lose three wickets, it can be frustrating,” said Pothas.

In the morning session it was Sri Lankan pacer Suranga Lakmal who threw up twice. He went to the dressing room briefly but returned to the field, bowling 14 overs and taking one wicket.

Groundsmen rushed on to cover the spot with sand and sawdust as smog in the heavily polluted Indian capital took centre stage for a fourth day in a row.

“He (Lakmal) obviously didn't feel very well,” Pothas said. “It's not easy, it's pretty obvious...there is no more to say about it. We just want to get on with the cricket.”

A doctor at the stadium examined three Sri Lankan players and said their vital signs were normal.

Skipper Virat Kohli, who made 50, declared India 's second innings on 246-5 after Rohit Sharma reached his half-century in the final session, setting the visitors a formidable victory target.

Hazardous smog

No Test team has chased down 410 or more since 2003, when the West Indies defeated Australia after making 418 runs.

Opener Shikhar Dhawan top-scored in India 's second innings with 67 on an easy-paced wicket. Apart from Lakmal, Lahiru Gamage, Dilruwan Perera, Lakshan Sandakan and Dhananjaya de Silva took a wicket each.

Earlier, Sri Lanka were dismissed for 373, conceding a 163-run first-innings lead to India who had declared on 536 for seven.

“I enjoyed playing that way (scoring quick runs). We would be trying hard to finish it tomorrow as we are in good situation with three wickets down,” said Dhawan.

He conceded the ground was polluted and the team had to “adjust accordingly”.

“I would never say that there is no pollution in Delhi. Of course there is pollution, but during the winters there is a lot of smog,” Dhawan said. “When you are playing for country, you have to do your job.”

The Board of Control for Cricket in India (BCCI) said late Monday that New Delhi could be dropped as a venue during winter, when pollution across the region spikes.

BCCI secretary Amitabh Choudhary said venues would be reconsidered “in view of the situation which was encountered in the last two to three days”.

“The BCCI has been sensitive on the smog and fog matter over the years,” he added.

The board had earlier accused Sri Lankan players of creating a fuss over nothing, and vowed to write to the Sri Lankan board over the matter.