City's lifeline Delhi Metro came to a standstill yet again this afternoon after services were suspended for two hours due to collapse of the Northern Power Grid for second consecutive day, inconveniencing commuters. As the power grid collapsed at around 1 PM, Delhi Metro trains stopped on tracks, some inside tunnels, due to non- supply of power and passengers stuck in the trains were evacuated immediately. Nine trains stopped inside tunnels after power failure but they were brought to the near-by stations and all passengers were evacuated. The services, which were suspended a little after 1 PM was restored at around 3 PM with minimum frequency after partial restoration of supply from the Northern Grid.