Not generalising corruption, but in your sector is salary the only source of income for other employees? Are the employees corrupt in your office?
You must be a corruption free employee but what about others, they earn more than 28LPA?
Now, my suggestion to your query: Don't quit the current job. Meanwhile learning is not a bad thing. Learn from Scaler or free resources if you can dedicate 2-3 hrs 5 days a week(maybe some extra time on a weekend). And, do some freelancing if you find. 2-3 years down the line, observe if you like this lifestyle and able to make good money. Then, only decide on leaving your current government job.