My boss recently reduced my salary. I'm totally very confused because their was no clear reason for doing that. Kindly advice me on the way forward.

lots of criticism of your boss/job here.
understandable—on the surface, this doesn’t sound like a great environment. perhaps the best thing might be... to leave.
also good for commenters to understand the context better. sometimes paycuts are honourable & needed to keep the business afloat.
during early covid the adbiz was paralyzed. my boss cut his own salary to zero. asked many people (including me) to take 20% cuts, asked some people who literally had no work to do to take some unpaid leave, all to make as few layoffs as possible. everyone understood & agreed. this all helped keep the company together. it survived & thrived. promises were kept. foregone pay was made up. it was a good decision. everyone worked together to turn things around. sometimes companies hit hard times but are still worth saving.
not saying that’s your situation obv. but what are you putting into your job? do you love your job? are you enthusiastic about it? how about the company itself? are you proud of the company? proud of tbe work you’re doing? could you be doing a better job? does it interest you to try? have you shared your feelings about your paycut, your job, your company etc with your boss. that might help you decide on next steps way more than all these comments based on minimal information…. more

The smartest human I've ever worked with!