The port city of Mumbai is home to Bollywood, stock markets and billionaire industrialists and migrant workers who dream of making it big. Bringing them together is a soft but chewy bread called pav.

A baker holds up a loaf of pav freshly baked at the Yazdani Bakery in Mumbai. A government plan to ban wood-fired ovens in bakeries as a way to curb pollution could lead to a price increase in the ...