There are a number of practices to ripen bananas. Dineshbhai Prajapati from Jeetpura village of Anand taluka uses lime water to ripen bananas. According to him, for 20 to 25 bananas, 50 gm lime should be diluted in 3 l water and the solution should be sprayed over the fruit. The bananas ripen in 3-4 days. After plucking the banana bunch from the tree, lime spraying should be done in the night. This is done just once. It is a traditional practice.
Formulation: 50 gm lime should be diluted in three-litre water.
Ingredients: Lime water (calcium carbonate) is used for ripening bananas
"Calcium carbide is widely used for artificial ripening of bananas." Maduwanthi, S.D.T. and Marapana, R.A.U.J., 2019. "Induced ripening agents and their effect on fruit quality of banana." International journal of food science, 2019.PAS 2:
"Most climacteric fruits in India are ripened with industrial grade calcium carbide. Industrial-grade calcium carbide usually contains traces of arsenic and phosphorus, and, thus, use of this chemical for this purpose is illegal in most countries."