Catalytic converters are meant to reduce the emissions of carbon monoxide, nitrogen oxides, hydrocarbons. In all western countries and most countries around the world it is regulated by a tight state policy in order to reduce pollution and protect public health. Check your country regulation on cars to find out if you can legally drive without one. Regardless of this having a full functioning catalytic converter represents an effort to protect the planet and fight against global warming. To protect the future of the planet and the ecosystem within which your kids will grow up you should make sure your car has a catalytic converter (and make sure it is recycled when worn out).