Complex sentence: Despite this, flooding is still common, especially in the summer rainy season, in lower-lying neighborhoods such as Iztapalapa, forcing residents to build miniature dikes in front of their houses to prevent heavily polluted rainwater from entering their homes.
Split into simpler sentences: Despite this, flooding is still common, especially in the summer rainy season, in lower-lying neighborhoods such as Iztapalapa. Many residents have built miniature dikes in front of their houses to keep heavily polluted rainwater from entering their homes.