Ill-effects of communalism : 

The ill-effects of communalism are as follows :

• Mutual hatred : When Hindus and Muslims fight for their respective interests, it naturally creates an atmosphere of mutual hatred and distrust. This hatred spreads fierce communalism and hence social peace gets disturbed. 
• Economic loss : Communal riots cost dear in terms of economic loss. Plenty of shops are burnt and a large amount of national property in gutted. In addition to it, government has to invest a hefty amount of money in controlling communal riots.
• Fatal for life : Hundreds of people are killed in communal riots. There have been no riots which have not caused massive bloodshed. Ranchi, Varanasi, Aligarh, Mumbai, etc are the recent examples of communal riots.
• Political instablity : An ill-effect of communalism is political instability. Communalism develops such circumstances or helps to develop such conditions which bring-in political instability in the country.
• Obstacle in national unity : Communalism is a strong enemy to national unity. National unity implies that all should live in mutual bond, all should ensure mutual good, whereas communalism stands with contrary objectives. Its conviction is that all communities should fight for their respective interests. 
• Threat to national security : 

India is a religiously diverse county. People of several communities live here. It is essential that these people live with harmony which is further essential for the development of the country. Fierce communal feelings and riots cannot allow unity to blossom. These communal clashes and tensions cause formidable danger to our national security. In addition to the above ill-effects, religion and communalism are also obstacles to the economic and industrial growth of the country. Communalism also adversely impacts our relations with other countries.