In the streets around a revered religious site in the Indian city of Mathura where a temple and mosque stand side-by-side, the handful of Muslim restaurants that remain are mostly empty or shuttered.

A ban on meat last year by the chief minister of Uttar Pradesh state, a Hindu monk who issued the order on religious grounds, has decimated their trade.

Now the saffron-clad Yogi Adityanath, up for re-election in key state polls next month, has turned his attention...