This chapter argues that the right to a clean environment is pivotal for every person in Indonesia, as it is guaranteed by Article 28H of the 1945 Constitution of the Republic of Indonesia. Moreover, in the context of the corporate field, this right is further elaborated in Article 74 of the Law on Limited Liability Companies, and Article 2 of the Government Regulation on Corporate Environmental and Social Responsibilities (CESR) for Limited Liability Companies. Both regulations stipulate that companies must have CESR programmes. Those provisions are intended to ensure that the company has the obligation to protect the environment, not merely focusing on the business side. However, neither regulations have substantive requirements on CESR itself. This chapter discusses how the absence of these substantive requirements on CESR will affect how the government ensures the fulfilment on the right to a clean environment through the company’s programme on CESR. To give a more comprehensive view, this chapter will scrutinize relevant cases in Indonesian courts, namely the civil lawsuit against PT Bumi Mekar Hijau and the citizen lawsuit against the government agencies/bodies by Gerakan Samarinda Menggugat. Drawing lessons from those two cases, this chapter concludes that here is an opportunity in enhancing CESR, namely by setting human rights due diligence as part of the substantive requirements in the CESR regulations in Indonesia so that the right to a clean environment can be ascertained in a full manner.