## 3 Result and Discussion
### Simulation Results of Inclusive Wealth and Inclusive Wealth per Capita  
The simulation results showed that the IW for Scenarios 1 and 2 were \(-\)78 billion USD and \(-\)63 billion USD, respectively, equivalent to \(-\)3.02% and \(-\)2.44% of the cumulative GDP (2580 billion USD) [(72)] in Bangladesh from 2020 to 2041 (Figure 9a). The results also showed that IW per capita values in 2041 were \(-\)1838 USD in Scenario 1 and \(-\)1479 USD in Scenario 2 (Figure 9b). Hence, IW would decline, imposing a massive loss on the economy. The decline in IW occurred because of the decrease in the DO/BOD ratio over time, ending at a critical value (0.024 and 0.07). This declining ratio destroys the river ecosystem, exerting negative impacts on IW generation [(43)]. IW comprises the produced, human, and natural capital. Figure 10a-c show the change in the values of the three capitals in Scenarios1 and 2 over 21 years. These results showed that human, natural, and produced capital decline over time. The corresponding values for the two scenarios were \(-69\), \(-4.3\), and \(-4.2\) and \(-58\), \(-2.7\), and \(-2.2\) billion USD, respectively, in 2041. Human capital declines the most (89% and 92%), and produced and natural capital account for almost the same proportion (Figure 10d). Figure 8: Simulation results of three scenarios, (**a**) DO, (**b**) BOD, (**c**) Sustainable water quality and (**d**) DO/BOD ratio. Figure 9: Simulation results of three scenarios, (**a**) IW and (**b**) IW per Capita. The primary reason for the decline in human capital is the effect of poor water quality on human health and life expectancy [65]. As the population density increases, river water pollution increases and affects a larger population. Similarly, the DO/BOD ratio decreases as pollution increases because of increased anthropogenic activities, which further decreases the water quality. Thus, water-borne diseases are likely to affect more people. The situation increases the years of living with water-borne diseases, resulting in a huge morbidity cost. Similarly, increased river pollution kills more people, imposing a colossal mortality cost. Natural capital declines as the value of the river ecosystem services decrease over time. We employed four river ecosystem services (supporting, provisioning, cultural, and regulating) to quantify the natural capital. Supporting services comprise carbon sequestration and air purification. Clean river water can absorb dust, nitrogen oxide, sulfur oxide, and hydrogen fluoride from the air, purifying the atmosphere [62]. Similarly, standard water quality leads to healthy aquatic and terrestrial vegetation, which capture CO\({}_{2}\) from the atmosphere and help ward against global warming and reduce climate change. The World Air Quality Report (2020) noted that Dhaka was the second-most air-polluted city globally in 2020. The report also showed that 13% to 22% of deaths are caused by air pollution, and the associated estimated cost is 7.4% of Bangladesh's GDP [73]. [PERSON] (2011) likewise noted that air pollution kills 15,000 people yearly, and Bangladesh could save 800 million USD yearly if air pollution was managed [74]. Figure 10: Simulation results in three scenarios, (**a**) Produced capital, (**b**) Human capital (HC), (**c**) Natural capital (NC) and (**d**) the contribution rate to IW of the three capitals. Provisioning services include fisheries, navigation, irrigation, and water supply. In Scenarios 1 and 2, the DO/BOD ratio negatively affected provisioning service values, inducing a decline over time. Regulating services comprise flood, water, and soil nutrition regulating value. Bangladesh is a flood-prone area as it is situated at the lower part of the Ganges delta. In both scenarios, the regulating service values declined as the polluted river system lacked flood, water, and soil nutrition regulation. Cultural services comprise recreation, mental and physical health. The polluted river negatively affected people regarding recreational, mental, and physical well-being.