Reliance Infrastructure-led Delhi Airport Metro Express, that will close down on Sunday, is expected to resume operations by third or fourth week of August, Urban Development secretary Sudhir Krishna has told NDTV. It was earlier reported that the services on the line were being stopped from Sunday for an unspecified period.The country's first public-private-partnership metro project has had a tumultuous journey in the past 16 months after it began operations in February, 2011.