Why was Sindh not divided?

There are multiple reasons as to why Sindh was not partitioned like Bengal and Punjab was. Some of them are as follows:

• The population of non-Muslims was not significant enough to merit a partition based on religious lines.

• The British left an undivided Sindh province likely as a compensation to the new dominion of Pakistan

• The role played by Muslim elites of Sindh ensured that Sindh would remain an intact porvince and not be divided in the manner Punjab and Bengal was.

For further reading check the following articles:

• Arab and Turkish Invasions
• First Battle of Tarain of 1191
• Second Battle of Tarain of 1192