Are they molting? Do you see a lot of feathers on the ground? every year the birds need to completely replace their feathers once. Depending on lighting conditions in your country, it is quite possible they are molting right now. When they molt they will not lay eggs for about a month.
Also coturnix need around 14 hours of light per day to lay eggs. How many hours of light are there in a day in Pakistan this time of year?
You need to understand the biology of the bird to properly answer your question. What light a birds eyes perceive effects most of their metabolic responses. The light hours of the day have changed rapidly over this last month. that tells the bird they need to generate new feathers for the coming season. your birds will molt every year around this time whether they are chickens, quail, or parrots. It's just how birds work. Give them a few more weeks to replace their feathers and they'll begin to lay again. Birds don't run on a digital clock so if they don't start laying right on your schedule you'll have to excuse them.