Studies show that substances like surfactants used in adhesives are toxic.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/no-stickers-fruits-vegetables-punjab-food-safety-dept-tells-traders
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/financial-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/food-safety
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/apple
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vegetables
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/food-safety-and-standards-act-2006
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health