In my view your essay is relevant since we are taking exam for Pakistan's civil service so focus should be on tyranny of customs in Pakistan.
I would like to add couple of points.
First , in introduction try to define what is "Custom" ?
Secondly, add a point in outline about tyranny of customs in different cultures, regions etc.
for instance

The custom of putting women's feet in a pair of tight wooden shoes all the time and for long periods, was universally observed in China and Japan till recent past and has not, perhaps, wholly disappeared even now. The purpose of this custom is alleged to be to prevent women from growing their feet to the usual normal size which may help them to walk and run like men and elope with a paramount at the first available opportunity.

You can look for more examples from on internet.

For introduction here are some points.

Customs, traditions and usages are the result of long experience of people living at a particular period. When certain things are found to be useful for a certain society, these things are being adopted by the people of that time.

Later on those practices are transmitted to the posterity, and then they take the form of the customs and traditions. Customs an therefore, the expression of the accumulated wisdom of our ancestors Our ancestors in all walk of life setup. Customs and traditions. Thus, we have social customs, political customs, racial customs etc.

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“All men are created equal; some work harder in preseason.”
Emmitt Smith