Which of the following is NOT a reason for slowing down of the Non-cooperation Movement?

Leaders of the movement shifted their focus towards domestic work thus created a void.

The correct answer is Option 2 - Leaders of the movement shifted their focus towards domestic work thus created a void.

Out of the options listed, Leaders of the movement shifted their focus towards domestic work thus created a void is not a reason for the slowing down of the Non-Cooperation Movement.

Here's why the other options are valid reasons:

Absence of alternative Indian institutions: When boycotting British institutions (courts, schools), a lack of established Indian alternatives made it difficult for people to continue their daily lives.
Lawyers rejoining due to financial pressure: Leaving their practice meant income loss for lawyers. Eventually, the financial strain forced some to return to British courts.
High cost of Khadi cloth: Khadi, the promoted alternative to British textiles, was expensive for many people, leading them to return to cheaper mill cloth.
While there were instances of leaders focusing on local issues, it wasn't a widespread reason for the movement's slowdown. The primary challenges stemmed from practical difficulties in sustaining the boycotts.