The public lighting system in Hanoi has been adjusted, with lights being turned on 30 minutes later and turned off 30 minutes earlier. Advertising lighting has been halved in intensity and they are completely turned off after 10 pm.
Lights in parks and flower gardens are operated at no more than half capacity and are totally shut off after 11 pm.
In streets around the lake, lighting has also partially turned off.
Art performance activities took place in the darkness on Friday evening.
The scene resembles Earth Hour on March 25.
The lighting around the lake mostly comes from nearby shops.
People walked around the lake in the darkness.