Prime Minister Narendra Modi’s national ruling party appeared poised to win an important regional election in India’s capital where voters had rejected Mr. Modi’s Hindu-first platform for nearly three decades even as it was expanding its footprint elsewhere across the vast country.

Early results on Saturday in elections for New Delhi’s regional assembly suggested that the Bharatiya Janata Party was on track to have more seats than the Aam Aadmi Party. Aam Aadmi, a small party, has governed the capital area for the past decade, though it has increasingly struggled against Mr. Modi’s efforts to crush it.

The political fight over who governs the capital region has come to epitomize the cutthroat nature of Indian politics.

Mudslinging rival parties have been competing for votes with handouts as well as with pressure tactics that include A.I.-heavy disinformation campaigns and outright jailings of politicians.

Meanwhile, delivery of basic government services for a region of more than 20 million people appears increasingly paralyzed.

This is a developing story. Check back for updates.