How can I legally stop food smell from neighbor's shop?

There is a shop near my house that runs a fast food stall, The strong smell of food (chowmein etc) comes to our house main door. Earlier they had a wall in their shop so direct smells did not come to our main door and area now they have removed it. They put the food stall inside the corridor of the shop and cook there. We have told them to either cover the wall so the smell does not come directly but they refuse and nor do they have proper exhaust inside the shop. Please guide what can be a solution to this and where we can complain?