This house is not on fire, Vastu shanti is going on.

While entering new home as per Hindu religion practices, 'Vastu shanti' is done.

Vastu shanti worship is originally a worship of lord and deity of directions, five element of nature as well as natural forces And other related stuffs.

The worship is done by having Hawan.

Some of the contents of the wikipedia link may not sound logical. (e.g. burning evil spirits).
But in old days (few centuries back) when there was not much population and nothing like electricity, concrete buildings, all homes had only ground floor.
Also at that time as the tree density was huge and there were much chances of having some wild animals near-by. For this ceremony as people come together for complete day and had fire in home, it could have been some threatening signal for wild animals.

Different herbal plants are used to lit up the fire So the smoke works as pesticide.
The smoke you see in the snap is this smoke.

But now thing are changed, we see more humans than trees.
As a part of tradition, still these processes are followed.