Every Diwali (the festival of lights in India) there is a competition held at IIT KGP among the different halls of residences. There are two categories. The first one, called Ilu (short for illumination) consists of each hall choosing a theme and then lighting diyas (mud lamps) mounted on chatais (grid like structure made from bamboo). The second category, called Rangoli consists of each hall decorating a large floor (normally the floor of the common room in the hall) with colors. Both these events are fiercely competitive and around a months preparation goes into this. Any artificial light seen during the judgement of the illumination contest disqualifies that particular hall. For the rangoli, a single insect inside the room can run havoc simply by walking over the colors. Of course you cannot switch on the fan since that would simply blow away the colors. The rangoli takes around a week to prepare and when it is washed away by the cleaning staff, the painters are visibly shaken and sad. This is one of the most bonding of events that a student body can ever have.