Today in our environmental science lecture, we'll discuss urban green spaces. Recent studies show that parks and community gardens in cities can reduce the heat island effect significantly. For example, a park of at least two hectares can lower surrounding temperatures by up to 3 degrees Celsius. Additionally, these spaces improve air quality and provide habitats for urban wildlife. However, the maintenance cost is often underestimated. Many cities struggle with budget constraints, so they prioritize larger parks over smaller neighborhood gardens, which are cheaper to maintain and more accessible for residents. In fact, small gardens can have a greater social impact per square meter.