Detailed Explanation:

❌ Statement 1 – Incorrect: Diphtheria has not been eradicated; India still administers the Pentavalent vaccine (introduced in 2011–12) which includes DPT (Diphtheria, Pertussis, Tetanus) component, indicating ongoing disease burden.

❌ Statement 2 – Incorrect: Chickenpox (Varicella) remains endemic in India; the Varicella vaccine is available but not part of the Universal Immunization Programme (UIP), and cases occur regularly across the country.

✅ Statement 3 – Correct: Smallpox was declared eradicated from India in 1975 (last case in 1975), and WHO certified global eradication in 1980; India played a key role in the worldwide eradication campaign.