You can find clay courts all around the world. Such as France. You can find them anywhere if you look them up
clay (clay courts) and tennis (tennis shoes)
Grass and Clay
Clay courts are known to be the slowest tennis court.
No, All Tennis courts are 78 feet long by 36 feet wide including the doubles tramlines. It may seem that grass courts are smaller either by the camera focal lengths used or the fact that clay courts hold up the ball bounce and so slow down the play.
Mainly two reasons. One, most people play on concrete or ceramic courts and the ball bounces a lot higher on clay courts. A more minor reason is the fact that some clay courts have a cover of sand, which in the end will make the a little bit slippery.
because it (the grass) reduces the friction between the ground and your shoes unlike clay courts.