Clean air and water are guaranteed rights under the Massachusetts Constitution, and lawmakers and activists hope these rights will soon become law. The Legislature is considering bills to protect low-income, minority and other at-risk populations from the effects of pollution. Local activists hope the proposals will help their communities and increase awareness of this issue.Almost three years ago, then-Gov. Deval Patrick signed an executive order authorizing environmental justice, which is defined as the “right to be protected from environmental pollution and to live in and enjoy a clean and healthful environment regardless of race, income, national origin or English language proficiency.”