IMC Journal (opens a pdf)
I am anxious.
I am anxious about traffic jams. Every year in the winters, I drive between 2,000 and 4,000 kilometers across India. The most stressful thing about a drive is a traffic jam – it binds one to a place with no control on how quickly an exit can be made.
Typically, three things cause a jam: (a) when the infrastructure is overwhelmed by supply of vehicles at a rate that it was not designed for (typically at tolls), (b) poor infrastructure (like potholes, diversions, blocked roads), or (c) accidents or breakdowns which occupy road space and mind space of travelers.
Anyone who starts a drive out of Mumbai knows that getting out of the city (and eventually coming back in) can be unpredictable. What makes an island city like Mumbai unique is that it has only a few key arterial exits: the exit would be towards Surat on the north, Nashik on the north-east, or Pune on the south-east. All of these exits are tolled, most of them have upgrade work going on which means there are blockages, and unfortunately, it is reasonably routine to find accidents or breakdowns which create long queues behind them.
Why, you wonder, are we talking about my driving getaways in an article on climate change.
This is because of the anxiety that, if ever a temporary mass exit is required out of the city, the evacuation infrastructure may get overwhelmed.
Mumbai disaster plan
The District Disaster Management Authority has prepared a disaster management plan (link; opens a pdf) for Mumbai. The document’s last available update online is dated Sep 30, 2022. The 500+ page document is a treasure trove of information and standard operating practices in case a disaster strikes the city. The plan is comprehensive on many dimensions: it details out the roles of the various agencies in myriad types of disasters including earthquake, cyclone, flood, tsunami, landslides, airport emergencies, terrorist attacks, and nuclear emergencies, among others.
Climate change
The document acknowledges climate change risk.
It says that “[I]ncreased intensity of climatic events like increased rainfall, floods, unseasonal rain or drought, intense heat, sea level rise, cyclonic storm surges and increasing outbreaks of tropical diseases and epidemics are all predicted outcomes of climate change and accompanying global warming. Greater Mumbai’s coastal location along with a large population living in close proximity to the coast render it highly vulnerable to a range of effects due to climate change, especially sea level rise and flooding. The fact that most of Mumbai is only a few metres above sea level and the city has four rivers that flow through it further increases its vulnerability to flooding.”
The document also recognizes that “Climate change intensifies the uneven distribution of risk, skewing disaster impacts even further towards poor communities and other vulnerable groups.”
Historical precedents underscore the gravity of these risks. The cyclone of June 6, 1882, resulted in catastrophic flooding and a death toll exceeding 100,000. More recently, Cyclone Nisarga in June 2020, while sparing Mumbai from direct devastation, served as a stark reminder of the city’s vulnerability to such events.
Various scientific research suggests that climate change is expected to make weather patterns uncertain and the preponderance of extreme climate events is expected to increase. Such events could include spells of intense heat (heatwaves coupled with the humid weather of Mumbai) or more severe or frequent cyclones, among others. It is during or just before these climate events (which may come with a warning of a few days) that a large population of the city may need to be evacuated.
Evacuation plans
The disaster management plan highlights the concept of a level of disasters: L0 is peace time, an L1 disaster can be managed at the district level, L2 requires the state, and L3 requires central government intervention. The document mentions “evacuation” 81 times: it is the responsibility of various authorities to ensure evacuation either before or during the disaster.
At the level of an L3 climate disaster, one way to avoid significant damage to people and property is to move people away from the area. In most cases, climate disasters will offer some notice (unlike, say, the cloudburst in July 2005). In such cases, it is possible that the citizenry makes evacuation plans for itself.
If a mass exit is required to be planned from the city, are the evacuation channels prepared to handle the rush? A mass exit does not mean that the entire city evacuates – a largish proportion (say greater than 10%) wanting to step out of the city over a day or two could create massive bottlenecks. The worst thing is a jam is the worry that it will only go longer which can makes for more reckless behavior. While some evacuation can take place through rail and air, a very large proportion of people may need to use roads. Since most of the arterial exits are tolled, can this become a bottleneck in evacuation?
Prepare
The good news is that the logistics infrastructure on all three evacuation routes has grown multifold over the last few years – Atal Setu, the Mumbai-Nagpur expressway, and significant flyover capacity on the Surat exits, are just some of the key examples.
Comfort in the answer to the question of whether the evacuation routes can handle the surge in traffic can only come from detailed and stress-tested modelling exercises – it may not be possible to do a test run of such a drill. Such models should account for human frailties in times of stress and disasters.
The Central government recently introduced Disaster Management (Amendment) Bill, 2024 in the Lok Sabha. The Bill empowers the National Disaster Management Authority to take stock of the entire range of disaster risks in the country periodically, including emerging disaster risks, which include “risks of those disasters that may not have taken place, but may occur in future due to extreme climate events and other factors.”
A “peace-time” conversation on evacuation plans and procedures can give the city stakeholders and respondents a working plan on how to respond in times of emergency.
We must all be anxious.
We must also be prepared.
Views are personal. The author is Distinguished Fellow, The Infravision Foundation. He thanks Jagan Shah for his inputs.
