Macro-level environmental factors that determine the area, species diversity and biomass of themangrove wetlands of India are analysed. On the basis of the spatial and temporal variations in these factors, major mangrove wetlands of India are classified. The Sunderbans and Mahanadi mangroves can be classified as tide-dominated, whereas Godavari, Krishna, Pichavaram and Muthupet mangrove wetlands can be grouped as river-dominated. The mangrove wetlands of Gujarat fall under the category of drowned-river valley type. Changes in some of the environmental factors, particularly changes in the periodicity and quantity of freshwater that flows into mangrove wetlands are examined, which indicates that reduction in freshwater flow would lead to reduction in the diversity of exclusive mangrove plant species. The current classification system can be utilized to develop strategies for long-term conservation of mangrove wetlands.