Twitter have launched trends for more 160+ locations and Pakistan got city based trends for the first time for following cities:
To change your Twitter trends login at Twitter.com from your computer and change trend to the location of your choice. You can choose city based or country based trends.
When you change your trends setting from Twitter web, it will automatically apply the new trends on your Twitter mobile application based on your selection of trends.
You cannot change trends from mobile site or mobile applications.