Ambuja Cements Ltd., part of the Adani Group, has agreed to acquire Orient Cement Ltd. in a deal valued at 81 billion rupees ($963 million), as billionaire Gautam Adani continues to snap up makers of the key raw material needed for India’s infrastructure push.

Ambuja Cements , India's No.2 cement maker, said on Tuesday it would buy a nearly 47% stake in rival Orient Cement for 37.91 billion rupees ($451 million), but analysts raised doubts about the deal winning regulatory approval.

Adani Group on Tuesday said it has agreed to acquire CK Birla group firm Orient Cement Ltd in a deal valued at Rs 8,100 crore, as billionaire Gautam Adani-run conglomerate snaps up smaller rivals to challenge India’s top cement maker UltraTech.