This is one of five sarovars in the City. This sarovar is in honor of Mata Kaulan, a Muslim woman, who was taken into care by the sixth Sikh Guru, Guru Hargobind on instructions of Mian Mir, a close friend of the Sikh Gurus and a pious and wise Muslim pir. All Sikhs are encouraged in their lives to do volunteer services at any gurdwara or in the greater society, and everyone you see working here is fulfilling that duty. It's likely possible that you can join in if you feel so inclined: you could enquire by asking the people outside peeling vegetables, or those washing dishes.