Wikipedia
Kansal
Kansal is a surname originating in northern India. According to legend, Agrasen had 18 children and divided his kingdom among them, hence establishing the 18 gotras. Collectively, the 18 gotras are known as Agarwal, one of the most influential trading communities in northern India.
Most people belonging to this gotra keep either Kansal, or Agarwal, or Gupta as surname. According to Agarwal customs, marrying a person from the same gotra is not appropriate.