Facebook Inc.’s $5.7 billion investment in a unit of India’s Reliance Industries Ltd. creates an e-commerce leviathan to take on Amazon .com and Walmart Inc. in one of the world’s most competitive internet arenas.

Amazon.com on Aug. 21 opened its largest campus building globally in the south Indian city of Hyderabad as it prepares for a furious expansion and battle with nemesis Walmart Inc. in one of the world’s fastest-growing retail markets.

When Walmart Inc. paid $16 billion for control of India’s e-commerce pioneer Flipkart Online Services Pvt. last year, the American retail giant got a little-noticed digital payments subsidiary as part of the deal.

Amazon.com resurrected thousands of suspended product listings in India by selling much of its stake in top local venture partner Cloudtail, a hastily arranged deal intended to comply with stringent new e-commerce regulations that upended the market.

Amazon.com’s and Walmart Inc.’s grand plans for India were thrown into chaos Feb. 1 after the country implemented new e-commerce regulations, which could cut their growth in the market by as much as half this year.

Walmart Inc. looks likely to take the next round in the battle for India’s retail market over rival Amazon.com.