Question: why the hole in the ozone layer over antarctica
[{'answer': 'chlorine', 'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 9, 'start_character': 141, 'end_paragraph_id': 9, 'end_character': 149, 'bleu_score': 1.0, 'section': 'Section::::Ozone cycle overview.\n'}]}, {'answer': 'bromine', 'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 9, 'start_character': 168, 'end_paragraph_id': 9, 'end_character': 175, 'bleu_score': 1.0, 'section': 'Section::::Ozone cycle overview.\n'}]}, {'answer': 'CFCs', 'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 2, 'start_character': 197, 'end_paragraph_id': 2, 'end_character': 201, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'halons', 'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 2, 'start_character': 211, 'end_paragraph_id': 2, 'end_character': 217, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'methyl bromide', 'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 74, 'start_character': 716, 'end_paragraph_id': 74, 'end_character': 730, 'bleu_score': 1.0, 'section': 'Section::::Public policy.\n'}]}, {'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 742450245516842986}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 663, 'bleu_score': 0.749477971551282, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 742450245516842986}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'start_paragraph_id': 74, 'start_character': 0, 'end_paragraph_id': 74, 'end_character': 1342, 'bleu_score': 0.941564133838635, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 742450245516842986}, 'section': 'Section::::Public policy.\n'}]}, {'provenance': [{'wikipedia_id': '44183', 'title': 'Ozone depletion', 'section': 'Section::::Public policy.\n', 'start_paragraph_id': 74, 'end_paragraph_id': 74, 'meta': {'evidence_span': ['After a series of scientific expeditions to the Antarctic produced convincing evidence that the ozone hole was indeed caused by chlorine and bromine from manmade organohalogens, the Montreal Protocol was strengthened at a 1990 meeting in London.', 'After a series of scientific expeditions to the Antarctic produced convincing evidence that the ozone hole was indeed caused by chlorine and bromine from manmade organohalogens, the Montreal Protocol was strengthened at a 1990 meeting in London.']}}]}, {'provenance': [{'wikipedia_id': '390949', 'title': 'Nimbus program', 'section': 'Section::::Contributions.:Ozone layer.\n', 'start_paragraph_id': 11, 'end_paragraph_id': 11, 'meta': {'evidence_span': ['Scientists conducted experiments from NASA experimental aircraft and proved that atmospheric chemicals such as the chlorofluorocarbons (CFCs) released from refrigerants and aerosol sprays did destroy ozone. As Nimbus 7 satellite observations accumulated between 1978 and 1994, it became increasingly clear that CFCs were creating an ozone hole each winter season over Antarctica. Not only that, but despite some year-to-year variations, it appeared the hole was becoming larger. The Nimbus measurements made clear how severe the ozone hole problem was.', 'Scientists conducted experiments from NASA experimental aircraft and proved that atmospheric chemicals such as the chlorofluorocarbons (CFCs) released from refrigerants and aerosol sprays did destroy ozone.', 's Nimbus 7 satellite observations accumulated between 1978 and 1994, it became increasingly clear that CFCs were creating an ozone hole each winter season over Antarctica. Not only that, but despite some year-to-year variations, it appeared the hole was becoming larger.']}}]}]