Since you are already studying Engineering, it makes sense for you to study Management after you complete your B. Tech course. B. Tech in itself is pretty rigorous...it requires you to dedicate all of your time & energy to get good marks and then finally get placed.
On another note, are you even interested in pursuing engineering in the first place? Because, if you are not, then you will be miserable in the next 2 years. In that case, we suggest that you drop engineering and opt for something where your interests lie. Even if that means wasting the 2 years of B. Tech. Atleast you will do something that you are passionate about.
At the UG level, you can opt for BBA, B. Com, Maths (H), Statistics (H) etc. After passing that the best option is MBA from a reputed institute. You will need to take an MBA entrance exam and basis its scores, you will get admission to any of the reputed B schools in India.
The reason why we are suggesting against a distance education in management or a UG Diploma is that there are lakhs of management gradutes in the country today. And not all of them have been able to get a footing in the industry yet. It is challenging no doubt, but any lesser qualification will just take away your chances of getting a good job. So we suggest that if you have to do something, do it with your whole heart! Good luck!