#4 How much domestic trash is collected in India annually in tons?

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Solution

The variables needed for this problem are:

- How much trash one person throws out each week

- The number of households in India

In India, trash is usually emptied everyday. The size of the average dustbin stands at about 100 liters. So, a person can be assumed to generate a waste of 100 liters everyday.

Or, about 0.10 cubic meters.

In one year, that's about 0.10 m^3 * 360 days

Or about 36 m^3 of un-compact garbage per year is generated by a single Indian.

Let's try to find the density of that garbage. All that uncompressed garbage of about 100 liters can be reasonably assumed to be 10 kg taking into account the fact that

- trash is mostly not liquid

- trash bins have airspace

Or, the average density will be about 10 / 100 = 0.1 kg / litre

Or, 0.1 kg / m^3

Or, 0.1 ton / m^3

In one year, an Indian can thus produce about 1 ton of garbage.

With a population of 1.38 * 10^9 people , the total number of households can reasonably be assumed to stand at about 10^8 (A majority of India's population is rural and rural families are often joint families living in the same household)

Or, the total mass can be about 1 (garbage generated) * 10^8 (household number) tons of garbage generated per year.

The actual estimate for waste generation according to Press Information Bureau stands at about 62 million tonnes.

Our answer is off by a factor of 10. Yet it is a reasonable guess to make. (To learn why, click here)