Why should the windows are opened on the

 hill side area and also on the elevated areas ?

The  cold is  less on the mountains and

also on the elevated areas.

That can be experienced if

 we live on the mountain side.

Not only the cold  is less but also  the

oxygen falls down  on those areas.

That atmosphere causes for suffering diseases.

 Even the youth also suffers from the

sickness due to the less oxygen and

the atmospherical elements.

So, compuslorily,  those who live on the

hill side areas  must open the windows

of their houses for getting good weather inside.

So, What  the eleders say that if  we sleep

 without opening the windows there

will be chances that the ghosts will come

 into the houses and may not go outside, 

by saying this they make us to

open the windows at nights also.

If we visit the pilgrimage places like

 Kedarnadh, Badarinadhm, Yamunotri,

Gangotri, Amarnadh etc.,  we can

notice the above things and we can be experienced also.