How to Optimize a Big City Mobile Game to Work Smooth?

Hello developers,

I am creating a basic Car Racing game with a track including a big city. During run time in stats it is showing 250k Tris and some thing around 145 Draw calls. Please give me idea how can i optimize it for smooth run in Mobiles. I have reduced the textures size and change the material shader to mobile compatible already. Please Help.

Thanks and Regards
Niraj Vishwakarma

You can use Occlusion Culling. It will disable object unless it is seen by camera.

More info :