Virat Kohli Sunday became the first international captain to hit six Test double centuries after he cracked a career-best 243 against Sri Lanka in New Delhi.

Virat Kohli and pollution added to Sri Lanka's misery as India declared their first innings on 536 for seven on day two of the third Test in smog-hit Delhi.

Kohli, 29, recorded his second successive double ton in third Test of the three-match series to go past West Indies great Brian Lara, who had five scored off 200 or more as captain.

In-form Kohli, fresh from his 213 in India's thrashing of Sri Lanka in the second Test in Nagpur, achieved the feat in the first session of day two after he pulled paceman Suranga Lakmal for a couple of runs.

The Delhi-born star, battling a back problem, batted for over seven hours from day one as smashed 25 boundaries in his 287-ball stay at the crease.

He was finally trapped lbw by left-arm wrist spinner Lakshan Sandakan in the afternoon sesison but not after surpassing his previous Test best of 235 against England.

Nicknamed King Kohli, the prolific run-getter has also scored double tons against West Indies, New Zealand, England and Bangaldesh - and all have come as captain since early in 2016.

He joined batting greats Sachin Tendulkar and Virender Sehwag in India's list of most double hundreds by batsmen in Tests.