Joe Root's second double-hundred in three matches helped England turn the screw on the second day in Chennai, as India conceded more than 550 in a single innings of a home Test for the first time since 2011.

Dom Sibley's dismissal in the last over of the first day had provided India with an opening, with England in danger of wasting an impressive start to the Test and with memories of their last visit to Chepauk - when they had racked up 477 and lost by an innings - still fresh.

But Ben Stokes opted to attack as the pitch started to show signs of wear, racking up 82 off 118 balls to take England to lunch unscathed, before Root's stand with Ollie Pope in the afternoon session helped them towards 500. India were eventually rewarded for their bowlers' hard work, taking four wickets for 52 in the evening session to leave England eight down, but their focus may now be on saving - rather than winning - the Test.

After driving the scoring rate on the first evening in partnership with Sibley, Root played second fiddle for most of his stand with Stokes. Having survived an inswinging yorker from Jasprit Bumrah early in the day, jamming his bat down late to keep it out via an edge into the boot, Stokes decided to put his foot down, and launched R Ashwin for a straight six inside the first half-hour.

There were signs in the first session that the pitch was not quite as flat as it had seemed on the first day, with puffs of dust from the surface and variable bounce for the spinners. Washington Sundar found some trampoline bounce from the footholes outside Stokes' off stump, while Ashwin was convinced he had trapped Stokes lbw reverse-sweeping, only to discover on review that the ball had hit him on the glove.

India burned their second review five balls later, when Shahbaz Nadeem's arm ball struck Root on the pad, but ball-tracking confirmed that it would have missed the top of leg stump. Stokes had two further lives, when Ashwin put down a half-chance off his own bowling and Cheteshwar Pujara, diving at full stretch, failed to cling on at midwicket. Stokes made his intentions clear by slog-sweeping Nadeem for six three balls after the second drop, before reverse-sweeping him for a pair of boundaries to bring up fifty.

Stokes continued to score freely after lunch, clubbing Nadeem over long-on and clipping Bumrah's slower ball through midwicket, but eventually holed out, slog-sweeping straight down square leg's throat where Pujara clung on despite initially fumbling.

Pope joined Root at 387 for 4 and unsurprisingly looked slightly rusty after six months out through injury. Kohli used India's third and final review when Pope swept to leg gully, but replays showed it had clearly hit the forearm rather than the glove.

Root, meanwhile, picked up where he had left off on Friday, happily milking Sundar and Nadeem for singles to keep the score ticking over. He was creative in playing reverse-sweeps and laps, but reached his double with a more orthodox shot, skipping down the wicket to swing Ashwin over the long-on boundary for six.

Root has scored 644 Test runs in five innings over the past four weeks, and his run tally in 2021 is more than double that of his nearest challenger, Steven Smith. As Rohit Sharma came on to bowl his part-time offspin before tea - which included an impression of Harbhajan Singh's action - it seemed as though India were becoming increasingly desperate in their bid to dismiss him. He also passed Alec Stewart to go third in the list of England's all-time leading run-scorers.

But the breakthroughs arrived after the interval. Having miscued an Ashwin full toss over Pant's head two overs before, Pope was struck in front while playing down the wrong line to a ball that didn't turn and was plumb lbw to leave England five down. In the following over, Root was pinned in front of leg stump by Nadeem, playing down the wrong line to one that skidded on, and while England warmly applauded his epic innings, India sensed an opportunity to expose the tail at 477 for 6.

Jos Buttler and Dom Bess rebuilt with an unflashy stand, with Buttler rifling Ashwin for a pair of fours, cutting balls either side of point. He benefitted from Kohli's enthusiasm to review when he got a thin edge behind off Sundar, which was given not out by umpire Anil Chaudhary to India's chagrin. Ultra-Edge confirmed that the decision would have been overturned if India had been able to review.

The stand took the total past 500 as India's hard graft continued, before the tireless Ishant Sharma took two wickets in two balls, extracting prodigious reverse-swing with the old ball. First, Buttler left one alone that he thought would miss his off stump only to look back and see it pegged back, before Jofra Archer made a mess of a similar delivery and was cleaned up first ball. Ishant's double-strike took him to 299 career wickets, though he could not complete 300 with a hat-trick after overstepping.

Jack Leach joined Bess, who offered a straightforward chance to Rohit at midwicket only to be put down, and with India's no-ball struggles returning in the final half-hour, they had added 30 together by the close. When they resume in the morning, it will be the first time in 20 years that England's first innings has extended into the third day uninterrupted.