NDMI measures vegetation water content and helps monitor drought stress. It uses the difference between near-infrared (NIR) and shortwave infrared (SWIR) bands. 

• Formula: NDWI = (NIR - SWIR) / (NIR + SWIR) 

• Range:
  +0.5 to +1.0 → High vegetation moisture

0 to +0.5 → Moderate moisture

Negative values → Dry vegetation or bare soil 

• Data Source:
  Based on Landsat 5, 7, 8, and 9 imagery (NASA & USGS) processed in Google Earth Engine for 1990–2024.