Design

I would say that urban design is at a very nascent stage currently in India. Not much opportunities are available in India for core urban design projects. This field is very well defined and well developed in USA, Europe, Singapore, Hong Kong, etc. However, slowly people in India are realizing the importance of urban design. Large masterplans of new cities or even large townships aspire to have some elements of urban design to make themselves more meaningful and relevant. Learnings from western countries are creating an impact. As far as employment goes, currently you won't have much role as a core urban designer. Very few private firms in India are doing urban design work.
Large master plans at government bodies are done by planners. But recently government bodies have started to employ urban designer for their projects. Recently, Pune municipal corporation had opened vacancies for urban designers to work on street design of Pune. Therefore, you may have chance of working at any government organisation or some of the private firms who are doing urban design work or you may continue to work as an architect/urban designer. You can also take up some research projects as urban designer with some think tanks in the metropolitan cities or even independently. But no doubt, doing Masters in urban design will add tremendous knowledge to yourself.