You should also make noise for a happy or sad event : wedding, death
For a new building or commerce, making noise is a way to advertise. It attracts by-passers. There might be other cultural explanation for all the noise (bring luck? Scare the bad spirits away?) but I can not tell you for sure.
Inaugurating the building where I am currently working on Wuyi Road
« The orchestra women » don’t even wear any hearings. They might already half deaf from all this everyday noise... :-)