The 4th World Hydrographic Day (WHD) will be observed today (Sunday), reports UNB.

The theme of this year's WHD is 'Hydrography-Supporting of the Marine Environment'.

Like all other member states of International Hydrographic Organisation (IHO) Bangladesh, the 70th member state, will celebrate the effective hydrographic activities to minimise damages to marine environment, said an ISPR press release.