The Montreal Protocol (1987) primarily addresses the phase-out of:
- Greenhouse gases
- Ozone-depleting substances
- Plastic waste
- Nuclear waste
Answer: Ozone-depleting substances
Montreal Protocol targets CFCs, halons, and other ODS to protect stratospheric ozone. It's considered one of the most successful environmental treaties. India ratified it in 1992. [[UNEP, NCERT Geography Class 11]]