Pollution of marine waters covering 70% of the globe and 97% of all the planet’s water resources is bound to affect the entire biosphere. This state of the planet’s environment poses a severe threat to life and a tough challenge to humanity. Pollution of rivulets, rivers, streams, and all seasonal waterways eventually ends up in the oceans, making the problem more complex. Vast quantities of toxic chemicals, crude oil, human wastes, and nuclear waste are disposed off in marine waters. Microplastics in marine ecosystem have now added a new dimension to the pollution scenarios of planet Earth. Marine pollution due to petroleum as a key pollutant is a multifaceted global problem. There are three causes of oil spills: Incidental, accidental, and intentional. In marine environment, petroleum products undergo four processes, creating multiple complexities in the ecosystem: Spreading, evaporation, solubilization, and residual material. Generally, oil pollution affects marine ecosystem in four ways: Fouling or oiling, oil toxicity, decreased dissolved oxygen levels, and reduced CO2 sequestration. Oil pollution in marine waters severely affects the populations of CO2 sequestering organisms, the photosynthesizers and chemosynthesizers, reducing CO2 sequestration potential of marine ecosystem by disrupting the biological carbon pump and damaging carbon sequestering habitats. Microplastics produced from primary and secondary sources are threatening marine ecosystem. Accumulation of plastic particles in marine waters is multiplying to the extent that a new “Plastic Island” in the Pacific Ocean, known as the Great Pacific Garbage Patch (GPGP), covering an estimated surface area of 1.6 million km2 has come into being.