NEW DELHI - Arvind Kejriwal, a civil society activist whose Aam Aadmi Party (AAP) had stunned mainstream political parties in the recent assembly elections in Delhi, will take over as Chief Minister later this week with the support of Congress, which had ruled the national capital for 15 years in a row before its rout. 45-year-old Kejriwal, a former Indian Revenue Service officer, met Lt Governor Najeeb Jung on Dec 23 and handed over him a letter staking claim to form government after his party’s Political Affairs Committee (PAC) met earlier and decided to take the plunge.