Open municipal solid waste (MSW) dumpsites are nowadays looming hotspots for water, air, and land pollution. Fresh and old MSW samples collected from a dumpsite in the coastal city of India were analyzed for moisture content, volatile content, energy content, elements, and toxic heavy metals. The compositional analysis results showed that fresh MSW consisted of 36% by weight bio-waste (food waste, yard waste, coconut waste) and around 30% recyclable materials (plastics, paper, cardboard, and metals). Approximately, 62% of the total fresh MSW was found to be combustible materials (plastics, paper, textile, rubber, cardboard, yard waste, and coconut husks). The analysis of old MSW samples collected from different depths (3–4 m and 6–7 m) showed the dominance of plastics (25–33%) and mixed residue (28–55%) having high energy content. Measurements of gaseous emission below 6–7 m from the surface indicated a higher concentration of methane (CH 4 :5.85 ± 0.12%) and lower concentration of carbon monoxide (CO: 3.82 ± 1.3 ppm), and hydrogen sulfide (H 2 S:10.15 ± 2.2 ppm). Haphazard dumping, waste characteristics, waste pile compaction processes and heat propagation due to deliberate fire may stimulate spontaneous fires. © 2018 Elsevier Ltd