CORRESPONDENCE CURRENT SCIENCE, VOL. 120, NO. 2, 25 JANUARY 2021 249 Microplastics pollution pathways to groundwater in India Plastics are typically organic polymers of high molecular mass, but they often con- tain other toxic substances which may disturb the ecological resilience. Due to the high volume of plastics being used, microplastics are emerging as pollutants with their small particles size (<5 mm), which is impacting not only the terrestri- al and marine ecosystems, but also the freshwater environs 1–3 . In addition to being present in different surface water bodies, microplastics have recently been reported in groundwater resources in India, which is normally being used for drinking purpose in Chennai, Tamil Nadu 1 . Ganesan et al. 1 reported plastic debris less than 5 mm as microplastic at the target zone (below the ground sur- face). Furthermore, they categorized microplastics as primary and secondary types 1 . The primary and secondary mi- croplastic types are categorized based on their production and degradation 4 . The microplastics content in groundwater was analysed using a number of samples to examine their actual concentration 1 . It was concluded that the microplastics content in groundwater was due to anth- ropogenic activities such as agricultural farming, fishing, wastewater treatment works, household activities, etc. 1 . Ganesan et al. 1 used cellulose nitrate filter paper (0.45 μm) equipped with vacuum filtration for microplastics extraction from the collected water samples. McCormick et al. 5 used the Neuston net (333 μm) for extraction of microplastics from surface water in Chi- cago River, USA. Subsequently, scan- ning electron microscope equipped with energy-dispersive X-rays was used to identify shape, colour and count of the microplastics, and also to determine the associated heavy metals adsorbed onto their surface 5 . Fibrous and fragment- shaped microplastics were reported in water samples of Chennai, and polymeric characteristics were determined using Fourier transform infrared spectroscopy for a better understanding of the potential sources of microplastics 6 . Furthermore, microplastics in ground- water due to contamination of the aquifer system, which is extensively used for drinking purpose across the globe, are being contributed mainly through waste- water treatment plants, septic effluent, etc. The transport and reaction of micro- plastics have also been found in the aqui- fer system. Microplastics act as a vector for transporting other contaminants, such as heavy metals, trace metals, etc. to both terrestrial and aquatic environs. Ganesan et al. 1 also confirmed the transport of heavy metals through adsorption onto the surface of microplastics and potential anthropogenic sources in groundwater at Pallipattu, Pallikaranai and Kovur, along with the presence of essential elements such as carbon, oxygen, sodium, magne- sium, aluminium, silicon, chloride, potassium and calcium in all three cate- gories of water (surface water, ground- water and commercial drinking water). Microplastics pollution is also re- ported in sediments of lakes, estuaries and coastal beaches in India 3,6 . Apart from sediments, limited studies have been conducted so far on samples from freshwater ecosystems 2 and ground- water 1 . However, several natural ecosys- tems, such as mangroves, coastal and freshwater wetlands, aquifer systems, springs, lakes, agricultural soil, surface water, etc. need to be studied to deter- mine the extent of microplastics pollu- tion and the potential strategies for remediation. The accumulation of micro- plastics mainly in sediments and water samples in various ecosystems has led to banning the use of plastics across the globe, including India. The Government of India has affirmatively banned plastic bags (<50 μm thickness) since 2016. The National Green Tribunal has prohibited disposable plastics since 2017. Assessing abundance and distribution of microplas- tics has significant potential for future environmental pollution-based research, disruption in ecosystem services, and ecological stability and resilience. In comparison, the exposure of microplas- tics to the food chain, along with human beings, has still been unexplored in the Indian ecosystem. Therefore, the recent study by Ganesan et al. 1 on microplastics in drinking water and groundwater would be a new discourse regarding nano- plastics from sediments, groundwater and surface-water systems, along with transfer into the food chain. Policies for proper implementation of solid/liquid waste management system need to be reinforced to prevent the transport of microplastics into the groundwater and minimize their presence in sediments, aquatic organisms and human beings. 1. Ganesan, M., Nallathambi, G. and Sriniva- salu, S., Curr. Sci., 2019, 117, 1879–1885. 2. Sarkar, D. J., Sarkar, S. D., Das, B. K., Manna, R. K., Behera, B. K. and Samanta, S., Sci. Total Environ., 2019, 694, 133712. 3. Sruthy, S. and Ramasamy, E., Environ. Pollut., 2017, 222, 315–322. 4. Cauwenberghe, L.V., Devriese, L., Galga- ni, F., Robbens, J. and Janssen, C. R., Mar. Environ. Res., 2015, 111, 5–17. 5. McCormick, A., Hoellein, T. J., Mason, S. A., Schluep, J. and Kelly, J. J., Environ. Sci. Technol., 2014, 48, 11863–11871. 6. Veerasingam, S., Saha, M., Suneel, V., Vethamony, P., Rodrigues, A. C., Bhatta- charyya, S. and Naik, B., Chemosphere, 2016, 159, 496–505. RAKESH KUMAR PRABHAKAR SHARMA* School of Ecology and Environment Studies, Nalanda University, Rajgir 803 116, India *e-mail: psharma@nalandauniv.edu.in Discovery of fossil dragonfly from India – a rejoinder Insect fossil records are relatively rare in India. Diverse arthropod taxa with more than 55 families and 100 species, except Odonata (dragonflies and damselflies) were reported from the 50–52 million- year-old (Cenozoic) amber Cambay Shale, Gujarat 1 . However, over 50 spe- cies of much older Odonata fossils have been discovered from geographically closer mid-Cretaceous Burmese amber (circa 100 million years) 2 . Modern Odo- nata appeared during the Triassic with