India, Nov. 9 -- Cascading delays affected over 500 flights arriving or departing the national Capital on Saturday, a day after the country's busiest airport was plunged into chaos when a critical communications system went offline.

The Air Message Switching System - the digital backbone that feeds crucial flight plan data to controllers - was fully restored to automatic mode by Saturday afternoon, officials said, nearly 48 hours after the system stopped transmitting information automatically to controller screens on Thursday afternoon. The system was partly restored late on Friday.

The government said in a statement on Saturday that the technical glitch, which occurred on the afternoon of November 6 and continued into the morning of No...