Prevention of Air Pollution from Ships

The International Maritime Organization (IMO) developed the International Convention for the Prevention of Pollution from Ships (MARPOL Convention) with the aim of preventing pollution of the marine environment by ships. Regulations for the Prevention of Air Pollution from Ships are provided for in Annexure VI to the MARPOL Convention and they seek to control airborne emissions from ships by prescribing limits on emissions.

Today, the shipping sector accounts for 12% of global sulphur dioxide emissions, 13% of global nitrogen oxide emissions and 3% of global carbon emissions.[1] Shipping fuel constitutes 7% of the global transport oil demand – however, global shipping emissions account for 90% of the transport sector’s sulphur emissions.

In view of these concerns, IMO adopted Regulation 14.1.3 under Annexure VI of the MARPOL Convention in October, 2016, which provides that sulphur content in fuel oils used on board ships cannot exceed 0.50% m/m on and after January 1, 2020.[2] India has a vast coastline with nine states and two union territories, with 73 of the 725 districts maritime ones where nearly 14% of India’s total population resides. As India is an energy deficient country, it has large shipping and maritime facilities where ships receive large cargoes and fuel shipments. To reduce rising sea levels, India has, pursuant to IMO Regulations, issued circulars with regard to shipping emissions.

The Directorate General of Shipping, Ministry of Shipping, Government of India, issued a circular in August, 2019, superseding all previous circulars for providing guidance to stakeholders for smoother implementation of compliance with the global sulphur cap from January 1, 2020. This circular is applicable to all Indian ships registered under the Merchant Shipping Act, 1958; all bunker suppliers registered with the Directorate General of Shipping, Government of India in accordance with Regulation 18 and Annexure VI of the MARPOL Convention; and all foreign flag vessels visiting Indian water.[3]


IMO 2020 will require shipping companies to switch over from the easily available and relatively cheaper higher sulphur fuel oil to a compliant fuel that does not exceed the 0.5% sulphur limit, unless they choose to install cleaning exhausts or scrubbers.[4] The refineries will also have to alter their production accordingly in order to meet the growing demand for compliant fuels. The following details possible options for complying with the IMO 2020:

  1. Installation of Scrubbers

Scrubbers consist of an exhaust cleaning system that processes high sulphur fuel oil to reduce its sulphur content by scrubbing off the excessive sulphur. They can be a viable option for shippers as they will not have to do away with the existing practice of using the relatively cheaper high sulphur fuel. The installation of a scrubber, however, does require a high capital investment and is mostly suitable for ships with large engines. Further, certain types of scrubbers like open loop scrubbers discharge the effluents into the sea and thus will have to be avoided as they end up polluting the waters.

  1. Low Sulphur Fuel Oils

The shipping companies can switch to using low sulphur fuel oils or other distillates like marine gas oil and marine diesel oil that are available for marine use with a sulphur content that meets the prescribed limit. This option will not require any technological modifications to the ships and will hence save the ship-owners from incurring significant capital investment. However, the cost of these fuels is likely to go up due to the surge in demand as the deadline for compliance approaches. The feasibility of using low sulphur fuel oils is also contingent on their availability as refineries will have to keep up with the rapid increase in demand.

  1. Alternate Fuels
  • Liquefied Natural Gas (LNG)

LNG is one of the cleanest alternative fuels owing to its negligible sulphur content. Its usage, however, requires the installation of cryogenic storage tanks, which require a high capital investment. LNG also needs specific bunkering and transportation infrastructure, which currently remains underdeveloped and is only available at a limited number of ports globally. Methane slip is an issue that comes with the use of LNG but it can be avoided by upgrading ship engines. This is likely to add to the operational costs incurred by the ship owners. Initiatives for setting up LNG bunkering facilities and infrastructure are underway in the European Union (EU) and the Middle East, and its use is expected to grow in the coming years.

  • Methanol

Methanol has a low sulphur content and requires relatively lower capital investment. Its storage may take up additional cargo space and fuel tanks may need modifications. Although low in sulphur content, the use of methanol does lead to greenhouse gas emissions, which do not make it suitable for long-term use as the IMO seeks to cut down greenhouse gas (GHG) emissions in the near future.

  • Hydrogen

Hydrogen is another clean fuel with minimal emissions. The adoption of hydrogen as a marine fuel is still at a nascent stage as its use requires marine fuel cells, and specific storage and bunkering infrastructure, which remains underdeveloped at most ports. Opting for the use of hydrogen will also entail incurring heavy capital costs. The transition to hydrogen is expected to gain momentum with the growth in technology and development of adequate infrastructure for its storage and transportation.

In order to comply with the prescribed sulphur limit, ships will have to either switch to low sulphur oils or distillates, alternate fuels or invest in adequate technology for cleaning up excessive sulphur content in existing high-sulphur fuels. Any such transition is going to increase operational costs, which will in turn have an impact on global freight charges. The growth in demand for cleaner fuels will be wider and more rapid as compared to their supply, thus causing a price hike for at least the initial transitional years. This increase in costs is likely to have a cascading effect, with the burden shifting to consumers. Further, the bunkering facilities for the cleaner fuels may vary at each port and unlike larger and developed ports, smaller ports may fail to serve the requirements of ships. This is likely to cause logistical disruption and raise operational costs for ships as they will have to make arrangements of surplus fuel in advance.

Shipping Companies Retrofitting Scrubbers

While most shipping companies are working towards procuring low sulphur blends and exploring the usage of alternate fuels like LNG and methanol, they have also invested in the installation of exhaust gas cleaning systems into their existing ships. NYK Line has retrofitted its bulk carriers with scrubbers while it also looks at contributing to developing LNG bunkering infrastructure. Mitsui has been analysing compliant fuel and scrubbers and has also been investing in LNG and methanol fueled carriers. Mitsubishi Heavy Industries Ltd., along with Mitsubishi Hitachi Power Systems, Ltd., has developed its own Large-scale Rectangular Marine Scrubber to be retrofitted in its ships. Further, other leading shipping companies like Maersk, Hapag Lloyd and Mediterranean Shipping Company have also invested in retrofitting scrubbers in their carriers. However, they have invested in low Sulphur fuel oil as well as they do not see the installation of scrubbers as a viable option in the long run.

Indian Refineries

It has been projected that complex refineries in India will be better equipped to meet the demand for compliant fuels as they have the capacity to produce cleaner fuels and distillates. Reliance Industries Limited (RIL) has the highest complexity amongst refiners in Asia and the United States (US).[5] It is thus capable of producing higher amounts of low sulphur fuels and distillates to meet the compliant fuel demand. Indian Oil Corporation Limited (IOCL) has conducted tests towards the production of low sulphur fuel oil and has taken measures to ensure the availability of compliant fuels for commercial supply as 2020 approaches. IOCL aims to supply cleaner fuel from its Haldia refinery on the eastern coast, and the Gujarat refinery on the western coast for international and domestic bunkering.[6] Refineries are also looking at cleaner alternate fuels like LNG.


Oceans have been a primary source of food and mode of transport, especially bulk trade transport, and have played a pivotal role in the distribution of energy resources and goods across the globe. The implementation of the IMO 2020 Regulations will help achieve global climate change objectives under the United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement. The Paris Agreement recognises the importance of “ensuring the integrity of all ecosystems, including oceans and protecting biodiversity”.

Therefore, the steps taken by Indian refineries supplying fuel to the ships are in the right direction. However, the full impact of the Regulations will only become clear in the year after they are fully implemented.

[1] The IMO 2020: Global Shipping’s Blue Sky Moment, Goldman Sachs, May 2018, <>.

[2] Regulation 14.1.3, Annexure VI, MARPOL Convention, 1997; Resolution MEPC.305(73).

[3] Engineering Circular No. 02 of 2019, ENC/OPP-MARPOL-38(5)/04, Directorate General of Shipping, Government of India.

[4] 2019 Guidelines for Consistent Implementation of the 0.50% Sulphur Limit under MARPOL Annex VI, Resolution MEPC.320(74).

[5] The IMO 2020: Global Shipping’s Blue Sky Moment, Goldman Sachs, May 2018, <>

[6] Fuelling The Maritime Sector: IMO 2020 & Beyond, KPMG, <>