Leasehold flat keeps smelling strongly of cigarettes

I live in a leasehold flat on the 3rd floor, every now and again my flat smells horribly of cigarettes and I suspect it’s a flat on the ground floor with a tiny little garden. There is no smoking allowed in the public areas but I’m assuming that doesn’t apply to this little garden?

Is there anything I can actually do other than try and talk to the neighbours? It’s extremely strong smell and definitely giving me second hand smoke.

I can close my windows but by the time the smoke is in it takes ages to leave and these flats are so insulated you need the windows open otherwise it gets really hot even in the autumn.