A Wall Street Journal article last week highlights five global cities with innovative ways to address their growing populations. Urbanization tends to lead to inequality and unaffordable housing, and it’s neat to see these places’ solutions.

Houston is unique among America’s big cities in its lack of zoning laws. Developers can build condominiums right next to treatment plants. While I don’t care for the aesthetic, it prevents real-estate prices from skyrocketing, and puts home ownership within reach of most of the population. (According to HAI, the average family in greater Houston earns 180% of what it needs to afford an average house there, compared with 70% in San Francisco.) No zoning also means faster development, enabling builders to respond quickly to market changes (for example, the recent decline in oil prices) and pursue projects per demand.

Taking the same approach on a smaller scale, Detroit is experimenting with “pink zones” that have found success in the UK. Pink zones basically eliminate zoning requirements and cut through swaths of paperwork. The city’s bankruptcy has enabled its fresh start, says famed planner Andrés Duany in the article.

A big surprise on the list is Medellín. Once the home of drug lord Pablo Escobar (who was killed by police in 1993), Colombia’s second-largest city is focusing its investments on in its poorest neighborhoods. Improved public transit, including a series of escalators and gondolas built into the Andean foothills, give people access to jobs and help fight poverty.

Vancouver and Singapore are also discussed. It’s a thought-provoking article, definitely worth a read.

Green Up Day is this Saturday, May 7. Grab a bag from your town clerk and pick up litter in your Vermont community!

Thanks to David Silverstein.