Q: why south-west side is kept less open?
Ans: According to Vastu Shastra north-east side of a house should be kept open and since the south-west side is heavy so this side should not be kept open.
The location of our country is in the north hemisphere. The sun since moves on its own axis so the solar ray from the south-west side falls in abundant throughout the year for long time in a day. Both in the summer and winter season the solar ray comes from the south-west side. At the same time the harmful ultra violet ray also comes from the same south-west side. So south-west side should be blocked. In Vastu Shastra it has been told that south-west side should be planted with big trees and high wall. While summer season the solar ray falls directly and this can be resisted by the shadow of the high trees remains at the south-west side. During winter the solar ray falls angularly and a little of the same can come through south-west side. Due to this reason the south-west side should be kept less open.