$199 for a luxury cruise? 'Voluntourism' eco vacations struggle to catch on

One cruise liner is offering passengers weeklong cruises centered entirely around volunteer work. But are these vacations as sustainable as they seem?

Cruise lines are among the travel industry's worst polluters, notorious for dumping insufficiently treated sewage into oceans or producing as much soot as 1m cars per day.

Now, cruise companies are seeking to offset that tainted image by offering "voluntourism" experiences. Passengers onboard Carnival Cruises' Fathom line, for example, can expect to tan by the pool in the morning, build water filters in the Dominican Republic in the afternoon, then dance on the ship's deck at night.