原因有很多了，有些人认为抽烟意味着自己长大了；有些人认为抽烟是一种消愁的方式；还有些人根本不知道烟对人体有害，至于为什么还是自己去了解历史吧！

because more and more people under great pressure

so many people, so much smoke. it is difficult to set a place for the smokers so you can see smoke almost everywhere but it getting better. less and less smoking is permission in public. smoking is fashionable in china, especially in youngsters which can make them like a adult. it also is considered as a culture by chinese artists and writers. no smoking, no inspiration. the most well-known poet 徐志摩 called smoking "to kiss the fire". 清人张潮写的《幽梦影》一书中，曾说：“花不可以无蝶，山不可以无泉，石不可以无苔，水不可以无藻，乔木不可以无藤萝，人不可以无癖。”here, 癖 is similar hobby in english. 如果你对此感兴趣的话，I mean the culture about 癖, 建议你去读林语堂(Lin Yutang)的书。

Most Chinese think it's common to smoke even though they know it does harm to health.Nobody will blame or stop your smoking. I hate smoking.

一点看法: 在古代的中国, 不管是强盛还是衰弱的朝代, 吸烟是很不普及的, 自从清朝末年, 鸦片大量进入中国之后, 大部分的中国人不分男女地吸食鸦片, 中国人种的体质在近200年的遗传之后, 人体对慢性毒药就产生了一定的依赖, 于是中国人比西方人更容易接受烟这种东西. 中国人吸烟的比例比西方人明显偏高. 奈何.