NEW DELHI: At a time when most Indian cities and towns show pollutants in the air due to emissions from different sources, two towns in Kerala - Malappuram and Pathanamthitta - have met the clean air benchmark of the Central Pollution Control Board (CPCB).

The finding is part of a book -- Good News Bad News: Clearing the Air in Indian Cities - brought out by Delhi-based research and advocacy organization Centre for Science and Environment (CSE), after making detailed assessment of 227 cities/towns of India on how they fare on parameters such as air quality, public transport, walk-ability, parking policies and fiscal initiatives.

The qualitative and quantitative assessment of air pollution level is based on survey in these cities/towns which are part of the air pollution monitoring grid of the CPCB of Union the ministry of environment and forest.

It was found during the assessment that there are very few cities\towns, which can be termed clean keeping PM10 levels (respirable particulates) as criteria. As far as other parameters are concerned, while SO2 levels have fallen sharply in many cities over the years, the NO2 levels have constantly been increasing in many cities.

Put together by the CSE's air pollution and sustainable urbanization experts, the book has come out with other startling facts. It said 78% of these cities\towns have particulate pollution levels that exceed the acceptable standards.

It also found that the bus transport ridership is declining in Delhi. On positive side, large numbers of people walk and cycle in Indian cities. Delhi has the highest number of cycle trips whereas Mumbai has the highest number of walk trips.

Referring to parking requirement of vehicles in cities, the book points out, " Delhi needs an area the size of 310 football fields for parking its vehicles. Chennai needs space equivalent to 100 such fields, Chandigarh 58 and Bhubaneswar 30".

Highlighting these facts, director general of the CSE Sunita Narain said, "India needs over Rs 3,00,000 crore to refurbish and renovate its transport network. Governments are expected to foot half the bill. But, can they do it?"

She said, "Air pollution has become the fifth largest killer, and the seventh biggest illness burden in India as per the Global Burden of Disease report, released in 2013. This book comes at a critical moment in the 'life-cycle' of Indian cities - it helps us understand how cities are moving ahead or stalling their progress, and what could be a possible roadmap for progress".

The book was released here by Harish Salve, senior advocate of Supreme Court and the amicus curiae on various environment-related cases on Thursday.

The CSE assessment has reviewed practices across the world, and finds that cities worldwide have started to take action to reverse the trend in travel choices.

The assessment finds that the "action in mega and big metros is more layered, diverse and extensive. This is partly because of the attention they have, investments they have drawn, and strident and aggressive public opinion and media pressure. Initiatives in smaller cities are often singular or limited in scope but with strong potential."