用以下短语造句：know about,on the land,in the sky,air po

I want to know about the air pollution in the following three areas: on the land, in the sky and under the ground.一句一句造句I know about your city.
There are many new houses on the land.
There is a bird in the sky.
The air pollution is very bad in our city.
There is a big factory under the ground.请一个短语照一个句子