Question: which problem does the montreal protocol attempt to remedy
[{'answer': 'ozone depletion', 'provenance': [{'wikipedia_id': '19856', 'title': 'Montreal Protocol', 'start_paragraph_id': 1, 'start_character': 282, 'end_paragraph_id': 1, 'end_character': 297, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19856', 'title': 'Montreal Protocol', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1547, 'bleu_score': 0.9179012360254831, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9751092990982849706}, 'section': 'Section::::Abstract.'}]}]