ISLAMABAD: The mega city of Karachi is at high risk from rise in sea level, prolonged cyclonic activity and increasing salt-water intrusion, according to a report of the Asian Development Bank issued on Tuesday.

The report - "Addressing Climate Change and Migration in Asia and the Pacific" - says environmental harm due to sea-level rise in association with storm surge impacts will be significant in the Bay of Bengal and the Arabian Sea, where cyclonic activity is projected to intensify.

The delta areas of the Ganges-Brahmaputra, Godavari, Indus, Krishna and Mahanadi rivers are likely to flood more often with increased monsoonal activity.

The hazard of coastal flooding is likely increase significantly in Bangladesh, in India in West Bengal and along the coast to Chennai and the coastal strip from Karachi to Mumbai, warns the report.

The Ganges and Indus rivers have significant salt-water intrusion and, with decreases in winter flows, the problem in these systems could become more significant, the report further warns.