cultivation for food crops, fisheries and forestry. Fallow land is , and are developed. The remaining are swamps and forest. Geology The city's soil has an average pH below 5, with red-yellow podzolic soil and regosol. A small area is bog soil and light-gray regosol derived from the deposition of sand and clay. Although such soil is less suitable for rice, other crops may be grown. The oldest formations are Permo-Carboniferous limestone, Late Triassic slate and Triassic-Jurassic granite. Composition of the granitic rocks includes dark-colored (occasionally green) biotite and amphibole. Hydrology The Rangkui River flows through the city, and the Pedindang River is in the south. They drain into the Baturusa River, which flows to the South China Sea. The rivers provided transport to markets, and make Pangkal Pinang prone to flooding (especially during the rainy season or at times of high tide). Climate Pangkal Pinang has a tropical rainforest climate (Af) with heavy rainfall year-round. Rain gets noticeably heavier from November to April. Administrative Districts At the time of the 2010 Census, the city was divided into five districts (kecamatan), but two additional districts were created subsequently. These are all tabulated below with their areas and their populations at the 2010 Census and 2020 Census. The table also includes the numbers of administrative villages (rural desa and urban kelurahan) in each district, and its postal code. Notes: (a) the 2010 population of the areas which later became Girimaya and Gabek districts is included in the figures for the districts from which they were cut out. Attractions Nganggung, a food-sharing tradition, is usually performed on religious holidays such as Lebaran and Eid al-Adha. The Qingming Festival (Ceng Beng, , in Hakka Chinese) is also celebrated. The Tin Museum is Asia's only tin museum, and was the site of the 7 May 1949 Roem–Van Roijen Agreement on the future of independent Indonesia. The 1936 Jamik Mosque, in Jalan Masjid Jamik, is one of the largest and oldest mosques in Pangkal Pinang. Kwan Tie Miaw temple (), on the Jalan Mayor Muhidin, is one of the oldest temples on the island of Bangka. Formerly known as the Kwan Tie Bio Temple, it is estimated to have been built in 1841 and dedicated to Lord Guan. GPIB Maranatha, originally the Kerkeraad der Protestansche Gemeente to Pangkalpinang, was built in 1927. After independence, the church's name was changed to Western Indonesian Protestant Church (GPIB)