The Blue Line (Line 3 & Line 4) is a metro rail line of the Delhi Metro, a rapid transit system in Delhi, India.Mostly elevated, it is the longest line (by total length) of the network and consists of a Main Line (Line 3) with 50 stations from Noida Electronic City to Dwarka Sector 21, with a length of 56.11 kilometres (34.87 miles) and a Branch Line (Line 4) consisting of 8 stations from Vaishali to Yamuna Bank, with a length of 8.51 kilometres (5.29 miles).[1]
The Main line (Line 3) was the longest line of the Delhi Metro network until 6 August 2021, when an unfinished section between Mayur Vihar Pocket 1 and Trilokpuri Sanjay Lake stations on the Pink Line was inaugurated, becoming one 59-km-long corridor.[2]