Energy is necessary to sustain all living and non- living organisms on earth. Energy can be categorised in to positive energy and negative energy. Both these energies originate from the sun.
The evening rays of the sun emit negative energy. According to vastu shastra, this energy is bad for the house as well as humans. Morning prayer with lighting the lamp is the way to welcome or absorb positive energy, while lighting the lamp in the dusk is to block the negative energy. It is popularly believed that it is not good to eat food at dusk. The reason behind this belief is that, at dusk, lot of negative energy gets accumulated and food taken at this time, when changes in to energy becomes negative, which adversely affects mind and body.
According to vastu shastra, it is the duty of the in mates to keep the house safe, away from the negative energy. There are certain ways to block this energy. Try to cancel or minimize the number of doors and windows in the south west direction. Open spaces in this direction should also be avoided. Planting banyan tree and Indian devil tree (Ezhilampala) also helps to block the flow of this energy from entering the house to an extent.