Air conditioners represent a troubling paradox -: they cool indoor spaces, but they heat up the climate. Most air conditioning systems operate via coolants, which often emit greenhouse gases – but not always. Indian manufacturing company Godrej is investing in eco-friendly propane for air conditioners instead of harmful fluorocarbons, or FC’s. Propane presents a greener alternative and helps protect the ozone layer. That's especially important in India where some four million air conditioners are sold every year. Still, propane is flammable, and critics say Godrej’s devices are dangerous for consumer use. The company is trying to reassure customers of their product safety by sending “Eco vans” throughout the country to distribute information.