A decade ago in India, a large number of cows were found to be dying on the streets from what was initially thought to be a mystery disease.
Closer inspection revealed that the cows were dying after consuming plastic carry bags.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/animals-eating-plastic-die-excruciating-pain
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/deccan-chronicle-hyderabad
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/andhra-pradesh
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/plastics
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/garbage
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/biodegradable-waste
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/diseases