Ph.D

It should be easy to get a job with a technical Ph.D., and the pay will be higher than with a Master's degree. However, for each 100 Ph.D's produced, there may be only 1-2 openings for faculty members each year. This leads to fierce competition for these slots.
Most Ph.Ds will go on to an industry. Industrial and government research labs allow Ph.Ds to continue doing research, but many Ph.Ds will do highly skilled (non-research) work in the industry.

Students with MBA by distance learning are eligible to seek admission in regular PhD if degree is done from a recognised university or Institute. In fact you can also do PhD by distance learning from IGNOU, AIMA-Aligarh university etc.

1. Anna University.
2. Madurai Kamaraj University.
3. Annamalai University.

Please refer to the link provided below for a list of courses offered by the university in question. You should be able to navigate to a Ph.D in Chemistry using the filters on the web page.
https://www.shiksha.com/university/gitam-university-visakhapatnam-24065

Please refer to the link provided below for a list of top colleges which offer Ph.D courses in management in India. You should be able to use the filters on the webpage to navigate to a college of your choice.
Link: https://www.shiksha.com/mba/ranking/top-mba-colleges-in-india/2-2-0-0-0

A candidate must have a 4 year or equivalent undergraduate degree from an accredited university. A candidate must have a prior undergraduate or graduate degree in a major with a substantial background in computer science & engineering. Those candidates who have completed Masters degree from a recognized university with above 55% marks are eligible for Ph.D course.
Please refer to the link provided below for a list of top colleges to pursue a PhD in computer sciences in India:
Link: https://www.shiksha.com/engineering/colleges/ph-d-computer-science-engineering-colleges-india

I doubt there should be any problem if you are pursuing a different subject in your PhD or M.tech. The most you can do is concentrate on your current studies and make sure you perform well in the current course.

There are very few universities in India which allow MCA graduates to do Ph.D. Most of the universities allow M.Tech students to register for Ph.D in CS. You may do M.Tech in CS after MCA to do Ph.D from a top Indian university.

Hi Sanjay, Germany, USA, UK are worth trying for.