Some environmental crises arrive with dramatic imagery—an oil slick, a collapsed dam, a televised apology. Others creep in through the mundane machinery of permits and contracts, unnoticed until the damage is irreversible. In Indonesia, that quiet destruction is happening at the scale of mountains.
The karst formations of Sulawesi and Halmahera—porous limestone hills riddled with caves and underground rivers—are being quarried at an accelerating pace to feed the country's booming nickel industry. These ancient structures act as natural water filters, channeling rainfall into the clean springs that sustain rural communities. But as Chinese-led investment transforms Indonesia into the world's dominant supplier of nickel for electric-vehicle batteries and stainless steel, the limestone that makes that transformation possible is being torn from the earth.
A boom built on limestone
Indonesia now hosts 147 nickel-processing plants, either operating or under construction. Roughly 120 of them use the RKEF method, which requires quicklime—produced by heating limestone—to remove impurities from ore in high-temperature furnaces. The remaining 27 use HPAL, a chemical process that demands even more limestone to neutralize the sulfuric acid used to dissolve the ore. Every one of these facilities depends on a steady, nearby supply of limestone, which is why new quarries are opening around every major smelting hub in Sulawesi and Halmahera.
Chinese companies dominate this landscape. Tsingshan Holding Group, the world's largest stainless-steel producer, anchors the Indonesia Morowali Industrial Park in Central Sulawesi—a flagship Belt and Road project that reportedly operates its own lime plants on site. CNGR Advanced Material, a Chinese battery-materials firm, runs operations both at Morowali and at the Weda Bay Industrial Park on Halmahera, roughly 700 kilometers to the east. Other Chinese players, including GEM Co., Zhejiang Huayou Cobalt, and CATL's Bangpu affiliate, process battery materials at Morowali, while Ningbo Lygend, in partnership with Indonesia's Harita Group, operates on Obi Island.
Chinese firms are estimated to control more than three-quarters of Indonesia's nickel-refining capacity. That means the demand for limestone across the region is being shaped largely in Chinese boardrooms.
Protected karst, unprotected future
Nowhere is the tension between industrial demand and legal protection more stark than in the Banggai Islands, off the coast of Central Sulawesi. The energy ministry has designated 38 permit areas for limestone quarrying there. By April 2026, 23 had become full business permits, and five were already producing. In 2023, the environmental group WALHI counted 28 companies seeking limestone-quarry permits across nine districts.
This activity continues despite the Banggai Islands enjoying some of the strongest legal safeguards of any karst landscape in Indonesia. A 2019 regional regulation protects the islands' karst outright, and a 2022 decree from the local government designates the area as a high conservation zone, complete with maps and coordinates. In April 2026, the Central Sulawesi provincial parliament asked the governor to cancel every limestone permit on the islands and freeze new ones, arguing that they violate both rules. That request has reportedly sat unanswered on the governor's desk.
A similar pattern is emerging around Sagea, a karst area adjacent to the Weda Bay park. The Bokimoruru cave system and a river that local communities rely on for drinking water are already covered by overlapping limestone and nickel permits.
The authors of this investigation are examining claims that limestone bound for Weda Bay is being quarried by a CNGR subsidiary, and that CNGR's Morowali operations have drawn financing from Bank Central Asia, Indonesia's largest private lender. Neither claim has been independently confirmed, but both fit a broader trend: the same Chinese firms that dominate Indonesia's nickel industry keep appearing near its most vulnerable karst.
Jakarta markets this industry as green—a contribution to the global fight against climate change through electric-vehicle battery production. But communities in Sulawesi and Halmahera see something closer to an old arrangement dressed in new language: a decarbonization push abroad that deepens extraction at home instead of easing it.
Karst is not simply rock waiting to be blasted. It functions as a vast natural filter, built over millions of years, that delivers clean spring water to generations of residents. No technology available today can undo damage to that system. Treating limestone as a generic input—with no history and no community attached—makes the destruction easier to overlook, and easier to repeat, permit by permit, under the banner of an industry still being sold as clean and green.
