In May 2026, the Attorney General of the State of Rio de Janeiro filed a Representation of Unconstitutionality (RI) before the Court of Justice with the objective of declaring the unconstitutionality of Municipal Complementary Law 281/2025, subsequently amended by Complementary Law 291/2025, both from the Municipality of Rio de Janeiro. The law promotes changes and flexibilities in the urban and building parameters established by the Master Plan, instituting a broad exceptional regime for the regularization, licensing, and expansion of buildings through the payment of financial compensation to the Municipality. The legislative changes allow the legalization of irregular constructions, the addition of sidewalks, horizontal and vertical expansion of buildings, the enclosure of balconies, and changes in real estate uses. 

According to the Public Prosecutor's Office, the legislation promotes structural changes in municipal urban policy without observing the constitutional limits applicable to territorial planning and without conducting studies that demonstrate the environmental and urban carrying capacity of the municipal territory, transforming exceptional regularization mechanisms into permanent instruments for expanding the city's construction potential. It pointed out that these mechanisms are operationalized through digital self-declaration procedures and impact assessments without sufficient technical guarantees. This scenario is aggravated by the inadequate regulation of the Neighborhood Impact Study and Report at the municipal level, which compromises the prior assessment of urban impacts and the observance of the principles of precaution, the social function of the city, and the democratic management of the territory. The public prosecutor argues that the law violates several provisions of the Constitution of the State of Rio de Janeiro related to the social function of the city and property, sustainable urban planning and development, popular participation, the protection of cultural heritage, the right to an ecologically balanced environment, and the guideline for reducing socio-environmental vulnerabilities.

It highlights how Technical Information from the Specialized Technical Support Group (GATE/MPRJ) indicates that the expansion of construction potential resulting from vertical and horizontal additions may cause damage to the urban landscape, increase soil impermeability, intensify the risk of flooding, and overload the drainage infrastructure, especially in areas already classified as having a high degree of climate vulnerability. It emphasizes that the flexibilities promoted by LC 281/2025 affect areas already subject to significant environmental and climate vulnerabilities, notably risks of flooding and the formation of urban heat islands, and highlights that the changes may contribute to increased local temperatures and the worsening of urban thermal discomfort. It concludes that such changes are incompatible with the Sustainable Development and Climate Action Plan of the Municipality of Rio de Janeiro, contradict guidelines aimed at protecting the landscape, addressing climate change, and preserving the natural and cultural values of the city, and violate the precautionary duty established in Advisory Opinion 23/2017 (OC-23/2025) of the Inter-American Court of Human Rights (IACHR). As a preliminary measure, it requests the suspension of the effects of the challenged regulation and, on the merits, a judgment declaring the regulation unconstitutional.


Action for Declaration of Unconstitutionality 3009429-27.2026.8.19.0000

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Action for Declaration of Unconstitutionality 3009429-27.2026.8.19.0000 - complaint

Filed

Brazil

Rio de Janeiro

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An aim to achieve a quantifiable outcome within a given time-frame, set by an institution such as a national government.

Policy instruments are techniques or tools used by governing authorities to promote certain policies in order to achieve predetermined goals. Put simply, instruments are how a government tries to achieve its goals, with this taxonomy being focused on national policy instruments.

Risk is the potential for adverse consequences resulting from the dynamic interplay between (climate-related) hazards, exposure, and vulnerability of affected human or ecological systems.

Groups  of people who are adversely affected by climate change or the response to it

A set of principles, processes, and practices that build economic and political power to shift from an extractive economy to a regenerative economy.

Justice is the ethical and political framework that addresses fairness, including issues of responsibility, rights, and structural inequity.

Renewable energy means all forms of energy produced from renewable sources in a sustainable manner.

Fossil fuel is a generic term for non-renewable energy sources such as coal, fossil gas, and oil (including crude oil, and petroleum products), that can be used for electricity and heat generation. Fossil fuels are hydrocarbons formed from pressurised and heated organic material buried over millions of years.

Molecules in the atmosphere that play a key role in the greenhouse effect by trapping heat radiating from Earth’s surface.

Area of the economy in which actors engage in identical or related activities.

In human systems, the process of adjustment to actual or expected climate change and its effects, in order to moderate harm, increase resilience or exploit beneficial opportunities. In natural systems, the process of adjustment to actual climate change and its effects; human intervention may facilitate adjustment to expected climate change and its effects.

The management and allocation of funds, assets and investments to meet various objectives

People who are less able to respond to the effects of climate change due to having limited financial or physical assets

Codes and standards are regulatory instruments that specify minimum standards to protect health and safety. This ranges from performance standards, which prescribe outcomes while allowing flexibility to achieve compliance, to the more prescriptive approach of technology-specific standards.

Zoning and spatial planning are both methods for guiding the distribution of people and activities in a space, and are regulatory restriction.

Aligning the skills of the workforce with the requirements of the just transition.

Either money or something of monetary value is transferred between two or more organisations, people or countries.

Conditions that enhance the feasibility of adaptation options. Enabling conditions include finance, technological innovation, strengthening policy instruments, institutional capacity, multi-level governance and changes in human behaviour and lifestyles.

Actions or measures to adapt terrestrial systems to climate change.

Actions or measures to adapt freshwater systems to climate change.

Actions to adapt human health, healthcare systems and well-being to climate change.

Actions or measures to adapt freshwater, coastal and marine systems to climate change.

Hot temperature extremes are daily maximum temperatures  that were exceeded on average once in a decade or once in 50 years, and includes heatwaves.

Extreme weather refers to events where a weather variable exceeds (or falls below) a threshold. Meaning it is significantly different from the average or usual weather pattern.

Social protection systems consist of policies that help people manage social risks in order to prevent poverty and maintain decent incomes and living standards

Social inclusion is the process of improving the terms on which individuals and groups take part in society—improving the ability, opportunity, and dignity of those disadvantaged on the basis of their identity.

Fossil gas, commonly known as natural gas, is a fossil fuel consisting chiefly of methane with smaller amounts of other hydrocarbons and trace gases, found in underground deposits.

Work that is productive and delivers a fair income, security in the workplace and social protection for all, better prospects for personal development and social integration, freedom for people to express their concerns, organize and participate in the decisions that affect their lives and equality of opportunity.

Jobs that contribute to preserving or restoring the environment. We include jobs which require a high amount of green skills or which spend much of their time on green activities, as well as jobs transforming polluting industries.

Any compulsory, unrequited payment to the government levied on corporations or individuals. This can be for environmental reasons, such as introducing a Carbon tax to set a price that emitters must pay for the greenhouse gases they emit.

This sector involves managing waste treatment, sanitation, pollution control and environmental cleanup.

Activities that involve planning, designing and building infrastructure, residential, and commercial structures.

This sector involves activities to move goods and people, alongside the storage of products.

Activities that provide lodging, food, and entertainment services to guests, including hotels, restaurants, and resorts.

This sector creates and distributes information and entertainment through television, radio, print, and digital platforms.

This sector involves activities that impart knowledge and skills to individuals, including formal schooling, vocational training and educational support.

Activities of government agencies and institutions that provide public services, enforce laws and manage public resources.

This sector includes firms and individuals offering specialised expertise in fields such as law, accounting, consulting, science and engineering.

Activities involving the management, development, and sale of property assets.

Activities that relate to the production of goods and services from forests.

This sector involves the distribution, treatment, and conservation of water resources.

Climate change impacts our society by disrupting the natural, economic and social systems we depend on. Physical hazards and underlying vulnerabilities can lead to increased resource competition for food and water, which can heighten the risk of conflict.

Action for Declaration of Unconstitutionality 3009429-27.2026.8.19.0000 - complaint

Policy instrument

Risk

Impacted group

Just transition

Fossil fuel

Economic sector

Adaptation/resilience

Finance