The 27 km line, which connects the northwest to the southeastern regions, is built for 25 stations.
Ali Emam told ISNA that the new stations, namely Mohammadieh, Molavi, Qiam Square, 17 Shahrivar, Mahallati, Ahang and Basij on the eastern side of Line 7 will become operational in six months.
"The seven stations account for about 8 kilometers of Line 7 on the far eastern side of the capital," Financial Tribune quoted Emam as saying.
Line 7 tunnel has already been constructed. "The seven stations will open as soon as the signaling equipment, escalators, air conditioning, and fire extinguishing systems are in place."
Last month the first three stations of the line were launched. With 15-minute headway between trains, commuters can now ride the subway from Helal Ahmar station in downtown Tehran to Tarbiat Modares station near Chamran and Jalal-e-Al-e-Ahmad expressway interchange, to Sanat Square in northwest Tehran.
Construction of Line 7 has been an unending saga since its partial opening in June 2017.
The premature launch by former mayor Mohammad Baqer Qalibaf amid the 2017 presidential campaign was strongly criticized by public transport experts and urban planners because it disregarded safety rules and protocols.
Qalibaf’s successor, Mohammad Ali Najafi, ordered the closure of the line lest the lives of commuters be endangered.
Tehran Mayor Pirouz Hanachi, who took over from Najafi, now says all safety standards have been taken into consideration.
Tehran subway comprises seven lines (line 1, 2, 3, 4, 5, 6 and 7) with nearly 100 stations. Line 6 and 7 are still under construction.
According to the metro officials, after completion of all the projects, the subway will carry up to 9 million passengers every day from the present 3 million.