Read the text and fill in the gaps with the correct form of the given words

Nowadays, people don't understand the scale of [ ] problems. The cities are overcrowding, the population is rising, the litter and garbage are collecting in the ocean. We don't see the real impact, but after some time we suffer from it. If we join small factors together, they may cause a [ ] problem. For example, India is one of the less [ ] countries in the world. Less than 20% of citizens don't throw garbage in the local streets and rivers. As a result, animals such as cows and goats eat people's leftovers. The garbage pales next to the humans' houses have led to serious socio-economic problems. Diseases started spreading faster, people don't have clean fresh water anymore. They travel miles away to get it.

The Indian cities are sprawling and in most cases, the economic base is [ ] of dealing with the problems created by their excessive size. Nowadays Indian [ ] in environmental communities teach citizens to sort, utilize and compost garbage. More than 1,500 colourful recycling containers and bins were installed in small neighbourhoods. After several months, the first results were published in the local newspaper. Now people are happy to live in a clean area without pollution and litter. But it's still difficult for some of them to collect and recycle plastic, paper and cloth in [ ] containers.