Amazon Inc. and Walmart Inc.¡¯s plans to dominate India¡¯s online retail landscape have been ambushed by Prime Minister Narendra Modi¡¯s political priorities heading into a tightening election.

The vote, which must be held by May, has increased the influence of local retailers that lobbied for growth-crimping curbs on the U.S. giants. On cue, India this month rolled out constraints on foreign e-commerce players, including Jeff Bezos-led Amazon and Walmart-owned Flipkart, which together control 70 percent of its online shopping.

The tighter rules, aimed at protecting small traders, may end up benefiting the country¡¯s richest man, Mukesh Ambani, who is building a homegrown competitor.