There's noise pollution, is there such a thing as 'smell polution' and is there anything i can do about it?

i live in a flat and have new next door neighbours. they moved in about 2 months ago and constantly cook indian food, all throughout the day and night, and it is stinking my flat out-somehow the smell gets through the walls, and into my built in cupboard, so i have had to wash all the clothes that were kept in there. I have had to move to another bedroom that is away from the adjoining wall as the smell was that bad, it would wake me up in the night. Is there anything i can do about this as it is unbearable. I'm also a bit wary about confronting them without coming across offensive. Please don't think its me being racist or anything as its not, but the smell is doing my head in.