Gurgaon got a little closer to north and central Delhi on Friday, 03/09/2010 with the opening of the Central Secretariat-Qutub Minar Metro corridor cutting the travel time between Connaught Place to the satellite city to just 50 minutes.       The 12.53-km fully underground corridor that passes through some of the densely-populated areas of south Delhi, which have been deprived of the Metro comfort till now, was integrated with the already operational Qutub Minar-HUDA City Centre line.        Urban Development Minister S Jaipal Reddy inaugurated the corridor and flagged off the first train from the Udyog Bhawan station in the presence of Delhi Chief Sheila Dikshit and DMRC Managing Director E Sreedharan.