Introduction

Municipal solid waste management systems of developing countries are gradually being formulated and attempt a high degree of systematization while simultaneously being faced with multitudinous set of socio-technical challenges. There are several agencies and systems to collect, manage, process, recycle, regulate, monitor and to dispose various components of municipal solid waste (MSW) and all these co-exist in every city (Chanakya and Swamy, 2011; Rana et al., 2015; Rana et al., 2017; Sharma et al., 2018; Rana et al., 2018). In this traverse towards finding workable solutions lie various imperfections. Unauthorized dumping in developing countries accounts for about 60-90% of the total solid waste disposal and it is required to understand causes, origins and solutions for disposal practices (Rajabapaiah, 1988; UNEP, 2000; Chanakya et al., 2015).

Cities in India face moderate to severe problem of unau- thorized dumping of MSW components. It is estimated that more than 60% of MSW is often disposed off in open dump sites and subject to natural degradation on vacant lands (Inanc et al., 2004; Chanakya et al., 2015). These disposal sites lack efficient waste processing systems and the natural degradation of dumped MSW along with formation of methane and leachates pose serious environmental and health risks. These dumps sometimes catch fire and continue to burn for more than a month (MPCB, 2014), even though urban local bodies (ULBs) have designated processing and disposal sites for waste treatment and disposal. Yet another issue with MSW in the developing world is inadequate capacity ranging from collection to treatment and disposal as these places are located at the edge and outskirts of the city and the current quantity of MSW received for processing generally exceeds the designed capacities. This results in unloading of unpro- cessed MSW nearer these sites, their pile up in specific locations and concomitant environmental issues. Frequent pro-tests and blockades of roads by 'affected' local citizens residing nearer these sites further aggravate the waste management leading to large scale "unauthorized" dumping in and around the city (Chanakya et al., 2014). In addition, these dump sites stop operations at sunset needing loaded MSW dump-trucks to stay overnight till the facility is reopened the next day. All these are conducive to transporters to dump MSW across the city and is generally termed unauthorized dump sites.

The occurrence and number of open dump sites has been reported to be dependent on many factors such as population of the city and density at the location, distance of dump site from the road network, width of roads, per capita income of nearby residents, unemployment rate, number of waste management facilities, distance from forest edge, distance from agricultural fields and topographic features such as valleys, ravines, etc. that allow anonymity of the dumping action (Ta- saki et al., 2007; Chanakya et al., 2011; Ichinose et al., 2011; Matsumoto et al., 2011). Involvement and active participation of local communities and making provisions for multiple and decentralized waste treatment facilities is expected to greatly dis-incentivize and consequently reduce the prevalence and practice of unauthorized dumping in vacant sites by increasing options and opportunities to dispose wastes, increasing access to these facilities and reducing transportation costs (Chanakya et al., 2011). Bangalore city has several topographical features such as abandoned deep quarries, unpopu- lated and inaccessible steep hill slopes, unclaimed land, abandoned irrigation tanks and tank beds, large unoccupied and uninhabited valleys along run-off courses, road-sides of lesser used peripheral roads are attractive locations for unauthorized dumping of wastes (Chanakya et al., 2015). The first reason can be nebulous ownership of such properties and second a persistent anonymity of these sites that allow continued use as easier to access dumping locations. Estimation of the quantity of wastes and the composition of waste accumulated on unauthorized dump sites and understanding of dump sites occurrence pattern are needed in order to strate- gize and activate an enforcement action plan and to propose alternative waste management options for the city. An attempt to measure the quantity and composition of waste in dumpsite were conducted in Delhi using 3D scanner (Nag- pure, 2019). However, hardly any study has assessed the dump site location pattern, area, nature, quantity and composition of waste dumped in the unauthorized waste dump sites. Several control measures, legislations, incentives and penalties have been attempted and yet, such unauthorized dumps being low cash-cost option, still prevail and need to be understand better.

The objective of the study was to determine the quantity and composition of MSW found at unauthorized dump sites and attempt to understand and predict their patterns. None of the earlier studies in this region have estimated, quantified or characterized wastes disposed off or remaining in unauthorized dump sites and/or assess pattern and their causes and/or environmental liabilities. This study will help to estimate the fraction of total waste dumped in this type of dump sites, identify possible causes and enable finding solutions to overcome the environmental impacts of MSW dumps.