A small meteorite falls to earth

It falls into remote area , nobody die, but the meteorote have a space bacteria that mutated and spread in the world.

The bacteria was not harmful on humans but it will melt iron and because of that all of humanity technology become un useable because they use iron....

It caused panic amd create chaos where government down and people do what they like.

The mc was a guy who attend kendo club, his dad was police. His school was suspended because of chaos.

There is a bunch of bully who do anything he wants, our mc stop them. The bully also hold grudge towards another strong kendo girl whom mc respect.

They try to rape her in the street at night, but beforr mc can save her, she beat all the bully and mc then go home without worrying her anymore.

At home the chaos is spreading, mc parents leave home to check things amd mc after 2 days without contanct decided to go to town and check things because he worry on his widowed aunt and niece.

He save an abandoned girl who seems seperated from her parents. I remember the manga title was kinda have blue sky on it.