Baoli in Hindi means stepwell. Built by successive rulers of Delhi to provide constant water supply to the city, baolis are an important aspect of Delhis architecture. Though not as ornate as the medieval Gujarati stepwell or vav, Delhis baolis are, nevertheless, unique and grand in their structure.
A baoli consists of two parts: A vertical shaft from which water is drawn and the surrounding inclined subterranean passageways, chambers and steps which provide access to the well. The galleries and chambers surrounding these wells are often carved profusely and become cool, quiet retreats during summers. The chambers in some of the baolis are seven or eight levels below the ground level and thereby provide the much needed relief from summer heat.
There are more than 30 baolis in Delhi. Originally used for storing rainwater, a majority of these are in ruins now. The oldest existing baoli of Delhi is Anangtal near Mehrauli, built in the 10th century during the reign of the Tomar dynasty. Gandhak ki Baoli near Qutab Minar - so called because of the smell of sulphur in water - and Hauz-i-Shamsi in South Delhi are two of the other old baolis. Some of the best preserved baolis are Rajon Ki Baoli in Mehrauli, Hauz Khas Baoli near Deer Park and
Ugrasen ki Baoli near Connaught Place.
Baolis can also be seen in Lucknow, Agra and Fatehpur Sikri.