Starting on the day on 237 for six, Root (77) and Buttler (70) stitched a 134-run seventh-wicket partnership helping the hosts stretch the first innings lead to 173 runs after a lot play was lost due to rain yesterday.
Pankaj (2-99), who made his debut in the last Test at Southampton, finally took his maiden wicket late in the morning session when he sent Root caught behind on a rising delivery that was sliding down the leg side.
The figures of other Indian bowlers though were not that impressive as they were made to toil on a day when Root and wicketkeeper-batsman Buttler, who scored his second fifty in his 2nd Test, scored heavily.
Bhuvneshwar Kumar (3-75) and Varun Aaron (3-77) couldn't add to their tallies from the first two days. Ravindra Jadeja (0-29) was the other bowler deployed as strangely enough Ravichandran Ashwin (0-28) didn't get a bowl today.
But once they did get it, India were still ineffective having allowed the two batsmen to settle down. Root-Buttler then kicked on and smacked 39 runs in the next ten overs. The 250-run mark came up in the 81st over while their 100-run partnership came up in the 85th over. They were helped along by some poor fielding too as Buttler was given two lives - on 34 and 45 - in this interim.
The second was far easier though, in the 89th over, as Buttler ran back for two-runs but Dhoni failed to collect cleanly from Aaron's throw and missed a clear run-out chance. Two overs later then, Buttler brought up his half-century off 108 balls, with 6 fours.
The hosts are replying to India's first innings score of 152 as the five-match series is tied at 1-1.
