After Dalmianagar's factories
The Rohtas district page says that until 1980 Dalmianagar, next to Dehri, was one of the major industrial cities in India, with sugar, vegetable oil, cement, paper and chemical works, and that those factories are now closed. What the town kept was its position: the Sone, the barrage and its canals, the highway and the railway.
The businesses that grew on that position are small and conversational. A mill sells rice by the truckload to buyers it may never meet; a transporter keeps a dozen drivers and parties in touch at once; a taxi owner books families for the barrage and the fort. Each of them already runs on WhatsApp, from a single phone. The API is how that phone becomes a desk several people can work.