It's so easy, that until recently, schools would commonly burn their own rubbish where children played. Children touched ash. The people are just breathing ash. It was a big problem. There are, for example, several large incinerators in the very heart of Tokyo, with more on the way.
Incineration is the first stage in Japan's waste disposal program.
Landfill is the second. Residue from incineration mixed with other waste, is disposed of in mainly inland mountainous areas. But these areas are running out, and Japan has had to find new sites. Reclaiming land has been one convenient, but controversial way to use landfill. For years, Japan has actively extended its shoreline, created a number of offshore islands for the sole purpose of dumping waste.