The concept of sustainable urban development has evolved significantly over the past decade, moving beyond mere environmental concerns to encompass social equity and economic viability. Recent research suggests that truly sustainable cities must integrate green infrastructure with affordable housing and accessible public services. For instance, a study in Copenhagen demonstrated that bike-friendly policies reduced carbon emissions by 20% while also improving public health. However, critics argue that such measures often fail in rapidly growing metropolises, where land scarcity and population pressure prioritize short-term economic gains. Thus, scholars now emphasize adaptive planning, which allows for flexible responses to changing demographic and climate conditions. This approach, though promising, requires robust governance and community participation to avoid unintended consequences.