Comprehension — quick quiz

Read the passage and answer the question that follows: "Conservation of water has become a critical issue in modern times. While rainfall patterns have become unpredictable, human consumption continues to rise. Simple practices like fixing leaky taps, reusing water for gardening, and harvesting rainwater can make a significant difference. Schools and communities must educate citizens about the importance of water conservation before it is too late." Which word in the passage is closest in meaning to 'crucial'?