New York, Sept. 4 -- The eco-minded Prince Harry is embarking on a massive travel sustainability initiative in partnership with key travel providers. They aim to improve the practices of the global industry amid an ever-increasing number of travelers.

The Duke of Sussex picked Amsterdam, a city hit hard by over-tourism, to announce Travalyst at a news conference Tuesday with his partners, Booking.com; TripAdvisor; Visa; China's largest travel company, Ctrip; and the Ctrip-owned fare aggregator Skyscanner.

The long-term initiative is focused on tackling the travel industry's impact on climate change, improving wildlife conservation, and protecting the environment in top tourist spots around the world. It aims to increase the amount of to...