It's possible that you might still be able to secure admission to M.Sc. Electronic Science at SPPU (Savitribai Phule Pune University) without a caste validity certificate, but it depends on the university's specific requirements.

The most reliable course of action is to directly contact the SPPU admissions office or department handling M.Sc. Electronic Science admissions. Explain your situation and inquire if a caste validity certificate is absolutely mandatory for your category (OBC - Non Creamy Layer).

Look for information on SPPU's admission regulations or brochures for postgraduate programs. These documents might mention specific requirements for caste certificates and if a caste validity certificate is mandatory for your category.

In some cases, universities might accept alternative documents as proof of caste in the absence of a caste validity certificate, especially for courses like B.Sc. and M.Sc. These could be:

• Caste certificate issued by a competent authority (if it mentions your category)
• School leaving certificate mentioning your caste (if applicable)
  
  https://www.careers360.com/university/savitribai-phule-pune-university-pune
  
  I hope it helps!