England were struggling on 36-2 following seamer Irfan Pathan's twin strike before reaching 118-3 at tea, with Pietersen unbeaten on 43 and all-rounder Paul Collingwood yet to score.
England lost left-handed openers Andrew Strauss (18) and Alastair Cook (17) in successive overs from Pathan before Pietersen rallied his team along with Bell (38).
Bell, who made nine and one in the drawn opening Test at Nagpur, looked on the way to a respectable score until he misread a googly from leg-spinner Anil Kumble that clipped the off bail.
Ashes hero Pietersen launched a fierce onslaught on the Indian attack, firmly driving the seamers and using his feet effectively against spinners.
The free-stroking batsman punished debutant leg-spinner Piyush Chawla, sweeping him for a four and then swinging the next delivery for a six. He then lofted the same bowler over long-on for a boundary.
Chawla was replaced by veteran Kumble after conceding 20 in four overs, but there was no stopping Pietersen.
Skipper Andrew Flintoff, who became a father for the second time on Wednesday, had won a second successive toss on a good batting track.
Strauss and Cook began promisingly after the match started 45 minutes late due to morning showers, batting steadily and relying on singles and twos, before falling in quick succession.
Strauss threw away his wicket, edging while trying to cut a delivery outside the off-stump. Wicket-keeper Mahendra Dhoni did the rest with a low catch to his left.
Pathan struck again when he trapped Cook leg-before to have the tourists struggling. The 21-year-old, who made 60 and 104 on debut at Nagpur, contributed 17.
But Pietersen and Bell helped restore England's fortunes before tea was taken early due to bad light. Bell hit six fours in his 68-ball knock and Pietersen one six and six fours in his 63-ball innings.
India made three changes from the team that drew the first Test, bringing in middle-order batsman Yuvraj Singh, Chawla and seamer Munaf Patel, who also made his debut.
Mohammad Kaif, who top-scored with 91 at Nagpur, was left out along with Venkatsai Laxman and unwell seamer Shanthakumaran Sreesanth.
England replaced left-arm spinner Ian Blackwell with seamer Liam Plunkett.