The issue of emerging contaminants (ECs) in aquatic systems is expanding globally. This chapter looks at this subject using a comparative case study of Mumbai, India, and the Rhine River Basin in Europe to consider the differences between the effects of untreated wastewater in Mumbai and industrial runoff in the Rhine on ECs and the ecology. The objective of this chapter is to pull from these case studies to propose effective EC pollution reduction methods in both developing and developed countries in the world. Mumbai is an Indian metropolis with a dense population and much of its effluent ends up in the aquatic systems untreated. This effluent could include a mix of residential and industrial ECs which will be influenced by their ecological footprint. The European Rhine River Basin has a long industrial history which could influence the industrial runoff. This case study will pick apart the types of ECs, we find at each location. The ECs in Mumbai consist of pharmaceuticals, personal-care products (PCPs), and home chemicals while in the Rhine it majorly consists of heavy metals, persistent organic pollutants (POPs), and industrial by-products. This chapter will compare Mumbai and Rhine to consider the options that can effectively reduce the ECs. It will also provide viable solutions such as improved wastewater treatment and disposal systems for Mumbai and stricter regulations on industrial discharges along with continuous clean-ups for Rhine. Further, it will highlight the need for international cooperation on this environmental issue and its role in tackling it.