India, March 27 -- In one of the narrow bylanes of Andheri East, a restaurant has long served as an unassuming proxy for a city that runs on affordable meals. For over three decades, it has fed a cross-section of Mumbai: migrant workers grabbing a quick drink and meal after their shifts; mid-level executives from nearby Special Economic Zones (SEZs) outsourcing their domestic needs to its kitchen; and weekend patrons lingering over starters that begin with a drink. The owner, who prefers anonymity, employs workers from Mangalore who stay on the premises and send home their savings.

Until a few weeks ago, the kitchen ran smoothly on commercial LPG, consuming at least three cylinders a day. But with supplies through the Strait of Hormuz se...