The bar-graph indicates the prevalence / widespread attack of infectious diseases in two cities A and B. Observe it and answer the questions given below:

1. Dengue fever 2. Rat fever

3. Cholera 4. Chikungunya

a. What may be the reason for the disease in city A?

b. Which city needs a more effective system of waste-disposal and cleaning?

c. How can the disease be controlled in city A?

a) We can give reasons for the disease by thinking of the cause of spreads of these particular diseases:

i. The absence of safe supplies of drinking water:

Excreta of someone suffering from an infectious disease like cholera may get mixed with the drinking water used by people leaving nearby. This situation is more likely to happen if the safe supply of drinking water is absent in the city.

ii. Stagnation of waste water:

Mosquitoes breed in stagnated water and then diseases such as dengue fever and chikungunya spread. Mosquito bites transfer the virus into our bodies making us ill.

iii. Lack of proper waste disposal systems:

Unhygienic surroundings lead to breeding of rodents such as rats due to which disease such as rat fever spreads.

b) City A needs a more effective system of waste disposal and cleaning. We arrived at this conclusion by analyzing the bar graph that the diseases are more prevalent in city A. These diseases mainly spread due to unhygienic conditions, water stagnation etc. Therefore if we can provide a more effective waste disposal system (recycling, composting) and cleaning system ( proper drainage system to maintain water flow) then we can reduce the prevalence of infectious diseases in city A to a large extent.

c) The diseases in city A can be controlled by eliminating the reasons for their spread. So we can take following steps to eliminate the disease-causing reasons:

i. Proper drainage system

With a proper drainage system flow of waste water is maintained. Thus water does not stagnate and it can help in preventing various water-related diseases. For example, mosquito breeding will be reduced and thus diseases like dengue fever, chikungunya can be controlled.

ii. Availability of clean and safe drinking water

Clean drinking water will prevent the spread of water-borne diseases such as cholera.

iii. Waste disposal systems

To ensure cleaner surroundings waste must be disposed off properly. Waste must be dumped in sanitary landfills away from the city. Waste water must be treated first before dumping into rivers.