The foreground of this picture captures one of two ablution pools within the sehn of al-Jami al-Anwar. The one seen in the photo is situated in the western corner of the masjid.
His Holiness Dr Syedna Mohammed Burhanuddin RA wished to restore al-Jami al-Anwar not simply as a historic monument, but as an active, living place of worship that catered to the requirements of prayer. Foremost among these requirements is ritual purity through ablution. For this purpose, plans for an ablution pool, or hawd, were developed and one was built in the northern and western corners of the masjid. As the water rises at the centre of the hawd, it flows out through grooves created in the marble surface, each groove becoming a spout. Due to extensive usage, the ablution pools have been restored multiple times, most recently in 1437/2016. The 15th century Egyptian historian, al-Maqrizi, who has written extensively about the Fatimi Imams SA, documents the presence of installations for the provision of water within and around al-Jami al-Anwar.” (Extracted with minor edits from page 204 of ‘al-Jami al-Anwar-The Luminous Masjid’)