Yes, you can pursue an MTech in Environmental Engineering after completing a BTech in Aerospace Engineering in India. Here’s an overview of the feasibility and considerations:

### **Feasibility**:

1. **Eligibility**: Most Indian institutions offering MTech in Environmental Engineering do not restrict eligibility to specific undergraduate disciplines. As long as you meet the general eligibility criteria and have a background in engineering, you should be eligible to apply.

2. **Interdisciplinary Transition**: While Aerospace Engineering and Environmental Engineering are distinct fields, an engineering background provides a strong foundation in technical and analytical skills that can be advantageous in Environmental Engineering.

### **Considerations**:

1. **Career Goals**: Reflect on your career aspirations. If you are passionate about environmental issues and wish to work in areas such as sustainability, environmental management, or pollution control, transitioning to Environmental Engineering can be a rewarding choice.

2. **Curriculum Adaptation**: Be prepared for a shift in focus. Environmental Engineering will introduce you to topics like water treatment, waste management, and environmental policy, which may differ from your BTech coursework.

3. **Institutions**: Research institutions offering MTech in Environmental Engineering and review their admission criteria and course structure. Leading institutions like IITs, NITs, and other engineering colleges offer specialized programs with robust curricula.

### **Is It Good?**:

- **Career Opportunities**: Environmental Engineering offers a range of career opportunities in both public and private sectors, including roles in environmental consultancy, regulatory agencies, and industrial sectors focusing on sustainability.

- **Personal Fulfillment**: If you have a keen interest in addressing environmental challenges, this transition can be fulfilling and impactful.

Overall, pursuing an MTech in Environmental Engineering after a BTech in Aerospace Engineering is possible and can be a good decision if it aligns with your career interests and goals.