Inside the mosque, there are three mehrabs in the prayer hall and these are decorated with a central suspended kalash carved with floral motifs.

[3][4] Conservation work on the Lila Gumbaz was conducted in 1921, which involved, according to an Archaeological Survey of India report of that year, removing the concrete cover over the ribbed dome and replacing it with new concrete and plastering, and also replacing stone floor slabs in the interior of the masjid.

[7] ASI reports of 2006 indicate that extensive restoration works of many heritage monuments were carried out at the Lila Gubaz and also at the Jami Masjid, fort walls, Bawana Mosque, Kevada Masjid, Sikandar Shah Tomb and Sikander tomb, which resulted in a slight increase in tourist traffic to the sites.

Further pulverization was prevented by spraying on OH-100 (ethyl silicate) and also in a few cases deteriorated areas were filled with stone powder mixed with OH-100.

[5] Other treatment measures included removing insoluble salts using a 2% solution of sodium hexa meta phosphate, ferrous salts with a 2% solution of EDTA and removing bat excreta with a 5% solution of liquid ammonia and non-ionic detergent followed by a second stage of treatment by applying a mixture of ammonium carbonate and ammonium bicarbonate, with EDTA as an additive.