Operations of all domestic and international flights from Hazrat Shahjalal International Airport (HSIA) will remain closed for five hours each night for the next two-month beginning today for renovation of the runway lighting system.  "This directive will remain effective from 2am to 7am everyday till April 3. We've taken the steps to install the runway's central lighting system to enhance the capacity of flight management and improve the service standard of the passengers," said HSIA executive director Mohammad Quamrul Islam.  Flight operations of different airlines during this time have been shifted to other times of the day, he said, adding that usually seven to eight flights operate during this time.  For managing the pressure, he said all concerned have already been asked for better coordination so that passengers do not face any problem at the airport for a long time.  Sources said, upgrading the Instrument Landing System (ILS) of HSIA will help flights smooth landing even amid fog. All related government and private institutions, including the airport traffic department have been asked to work in coordination to make the journey of passengers smooth and uninterrupted, said Kamrul Islam.