单词quanlity拼错了（正确应为quality),还有时态不对.
no sooner.than 固定用法"一...就..."
引导时间状语从句,主句用过去完成时,"than"后面的从句用一般过去时
另外,内容和逻辑上个人认为存在问题.看起来想要表达的意思是：人们一开始保护环境,环境就变成高质量的了.想想也不可能啊.你昨天少往地上扔一张废纸,今天PM2.5就消失了?
就这个内容而言,no sooner than句型不太适合.如果一定要用,建议改为：
No sooner had people started to protect the environment than its quality became better.