Analysis of water, plankton, fish and sediment reveals that the Cauvery River water in the downstream is contaminated by certain heavy metals. Water samples have high carbonate hardness. Concentrations of all elements and ions increase in the downstream. Main ions are in the following order: Na > HCO3>Mg > K > Ca> Cl > SO4. Heavy metal concentration in water was Cr >Cu ≈ Mn > Co > Ni > Pb > Zn, in fish muscles Cr > Mn > Cu > Ni > Co > Pb ≈ Zn, in phytoplanktens Co > Zn > Pb > Mn > Cr and in the sediments the heavy metal concentration was Co > Cr > Ni ≈ Cu > Mn > Zn > Pb. Although, the quality of Cauvery River may be classified as very good based on the salt and sodium for irrigation, Zn, Pb and Cr concentration exceeded the upper limit of standards. Metal concentrations in the downstream indicate an increase in the pollution load due to movement of fertilizers, agricultural ashes, industrial effluents and anthropogenic wastes. An immediate attention from the concerned authorities is required in order to protect the river from further pollution.

Urbanization offers several opportunities for the growth of economic, social, and technology sectors, offering benefits to society in terms of better living and healthcare facilities, as well as employment opportunities. However, some major downsides of urbanization are overcrowding and environmental degradation. In order to realize sustainable and environmentally friendly urbanization, there is an urgent need for comprehensive land use planning and of urban settlements by giving due consideration to create and sustain urban green spaces (UGS) such as parks, gardens, roadside vegetation, etc. UGS play a vital role in reducing air pollution, mitigating climate change, and providing various ecosystem services. UGS are being deteriorated substantially due to booming urbanization in developing countries such as India. This review is focused on highlighting the many challenges in creating and maintaining UGS in the Indian context. It is a compilation of available reports on problems linked with poor land use and/or planning of urban settlements. The challenges associated with the management and maintenance of UGS are described. The poor and irregular watering of many existing UGS is one of the major issues among several others requiring immediate attention to resolve the problem of deteriorating UGS in some cities of India. As the groundwater resources are rapidly depleting because of ever increasing water demand, UGS are being dispensed with poor and irregular watering resulting in their deterioration. A list of possible solutions and prospects of UGS in cities aiming to become smart cities soon are discussed in this review. Efficient wastewater treatment and a non-potable reuse system are possible solutions for better prospects of UGS, and therefore, optimism of better cities with low to null urban heat island effect.

Assessment of heavy metal content in litchens and soil samples from various localities of Hosur Road, Bangalore south was undertaken. Topsoil samples (0-10 cm) were taken at various locations, the metals analysed were Cr, Pb, Fe, Zn, Ni and Cu. The geoaccumulation index of these metals in the soils under study residential areas indicated that they are uncontaminated with Ni, Zn, and Fe and moderately contaminated with Cr and Pb. In Industrial areas and traffic junctions the concentration of Fe, Pb and Ni was maximum. Heavy metal accumulation in few prominent lichens of some localities was analysed. Cr and Pb were maximum inChrysothrix candelaris(L.) Laundon, at the gardens of Madiwala and Silk Board junction with 95.29 and 623.95 µg g–1dry weight respectively. Fe and Cu were maximum inBulbothrix isidiza(Nyl.). Hale andPyxine petricolaNyl at Central Prison campus and Kendriya Sadan campus with 22721 and 338.12 µg g–1dry weight respectively,Lecanora perplexaBrodo at Infosis and Wipro Campus, electronic city have 531.5 and 634 µg g–1dry weight of Zn. While Ni and Fe were maximum in Arthopyreniaceae at Shanti Niketan of MICO Limited with 1100 and 23200 µg g–1dry weight respectively.

Elucidating the impact of Land Surface Temperature (LST) is an important aspect of urban studies. The impact of urbanization on LST has been widely studied to monitor the Urban Heat Island (UHI) phenomenon. However, the sensitivity of various urban factors such as urban green spaces (UGS), built-up area, and water bodies to LST is not sufficiently resolved for many urban settlements. By using remote sensing techniques, this study aimed to quantify the influence of urban factors on LST in the two traditional cities (i) Panaji and (ii) Tumkur of India, proposed to be developed as smart cities. Landsat data were used to extract thematic and statistical information about urban factors using the Enhanced Built-up and Bareness Index (EBBI), Modified Normalized Difference Water Index (MNDWI), and Soil Adjusted Vegetation Index (SAVI). The multivariate regression model revealed that the value of adjusted R2 was 0.716 with a standard error of 1.97 for Tumkur city, while it was 0.698 with a standard error of 1.407 for Panaji city. The non-parametric correlation test brought out a strong negative correlation between MNDWI and LST with a value of 0.83 for Panaji, and between SAVI and LST with a value of 0.77 for Tumkur. The maximum percentage share of cooling surfaces are water bodies in Panaji with 35% coverage and green spaces in Tumkur with 25% coverage. Apparently, the UGS and water bodies can help in bringing down the LST, as well as facilitating healthy living conditions and aesthetic appeal. Therefore, the significance of ecosystem services (green spaces and water bodies) should be given priority in the decision-making process of sustainable and vibrant city development.

Rising land surface temperature (LST), urban heat island (UHI) effects, and stress on surface-, processed-, potable-, and ground-water resources are some undesirable ecological changes due to rapid urbanization. Treating and reusing city-generated wastewater for maintaining urban green spaces (UGS) helps in reducing/preventing groundwater extraction, ensuring sufficient supply of potable water, and bringing down LST. However, the benefits of reusing treated wastewater in UGS for enhancing regulatory ecosystem services (RES) and ushering in a circular economy are yet to be realized. In view of these, the transportation costs of treated wastewater for irrigating the UGS of Panaji city—proposed to be developed as a smart city—were assessed. Field surveys were conducted at seven gardens/parks to collect the primary data on vegetation type (ground cover, hedge plants, and trees) and their daily water requirement. As the main focus of this study, a cost–benefit analysis of (a) drawing the groundwater using borewells versus use of treated wastewater from the city’s STP, and (b) two modes of treated wastewater transport: water tankers vs. pipeline was performed. Our analyses suggest that the copiously available 14 MLD treated wastewater from the STP, which meets all the safety standards, is far in excess of the current requirement of 6.24 MLD for watering the vegetation in all 17 parks/gardens in the city. Pipeline is an efficient (less energy, labor, and time) and economical (~47% more than water that is tanker-based) transportation mode. By utilizing the otherwise unused treated wastewater, which is processed at a cost of over USD half a million annually, the RES offered by the use of treated wastewater are (a) partially curtailing a combined loss of ~16 MLD due to the extraction of groundwater plus evapotranspiration (@8.86 mm d−1) from Panaji city’s 1.86 km2 UGS, and (b) reduction in LST ~3–4 °C in all of Panaji city. In addition, with the proficient and sustainable management of UGS and the meeting of many UNSDGs, the enhanced vegetation growth plus elevated carbon sequestration rates in the UGS are possible through the reuse of treated wastewater.