> As said in other threads, our grandmothers and mothers used to open all windows briefly every morning
This is a common practice (except in very cold or highly polluted parts of India) even today - and not just briefly, either - windows are often open until evening, until a bit before mosquito entering time. And some people again open windows after 8 pm or so, because the lore is that mosquitoes won't move much after that. But that is oldish stuff, and it can be different these days.
And even in those colder or more polluted areas, some people still do it.
This is a common practice (except in very cold or highly polluted parts of India) even today - and not just briefly, either - windows are often open until evening, until a bit before mosquito entering time. And some people again open windows after 8 pm or so, because the lore is that mosquitoes won't move much after that. But that is oldish stuff, and it can be different these days.
And even in those colder or more polluted areas, some people still do it.