(i) A seed ball is a seed that has been wrapped in soil materials, usually a mixture of clay and compost and then dried.
(ii) The seed is pre-planted and can be sown by depositing the seed ball anywhere suitable for the species, keeping the seed safely until the proper germination window arises.

Global warming is the current increase in temperature of the earth's surface (both land and water) and its atmosphere.

1. Use of noise barriers
2. Newer roadway for surface transport
3. Traffic control
4. Regulating times for heavy vehicles
5. Installations of noise barriers in the work place
6. Regulation of Loudspeakers

(i) Electronic waste is the new by product of the Info Tech society.
(ii) It includes a growing range of electronic devices from household appliances, such as refrigerators, air conditioners, cell phones, computers.
(iii) e-waste can be defined as the result when consumer, business and household devices are sent for re-cycling (e.g., television, computers, audio-equipments, VCR, DVD, telephone, Fax, Xerox machines, wireless devices, video games).

Discharge of sewage and waste water:
(i) Sewage, garbage and liquid waste of households, agricultural runoff and effluents from factories are discharged into lakes and rivers.
(ii) These wastes contain harmful chemicals and toxins which make the water poisonous for aquatic animals and plants.
Dumping of solid wastes:
(i) The dumping of solid wastes and litters in water bodies cause huge problems.
Discharge of industrial wastes:
(i) Industrial waste contains asbestos, lead, mercury, grease oil and petrochemicals.
Oil Spill:
(i) Sea water gets polluted due to oil spilled from ships and tankers.
Acid Rain:
(i) When the acidic particles caused by air pollution mix with water vapour, it results in acid rain.
Global warming:
(i) The increase in water temperature affects aquatic plants and animals.
Eutrophication:
(i) The increased level of nutrients in water depletes oxygen in water and this negatively affects fish and other aquatic animal population.

Indoor Air Pollution:
(i) It refers to toxic contaminants that we encounter in our daily lives in our homes, schools and workplaces.
(ii) (e.g.) cooking and heating with solid fuels on open fires.
Outdoor Air Pollution:
(i) It refers to ambient air.
(ii) The common sources of outdoor air pollution are caused by combustion processes from motor vehicles, solid fuel burning and industry.

Introduction:
(i) Sustainable development is concerned with the welfare of the present and future generation.
(ii) It aims at satisfying the luxury wants of the rich and the basic necessities of the poor.
Definition:
(i) Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
Goals:
(i) It is crucial to harmonize three core elements such as economic growth, social inclusion and environmental protection.
(ii) A set of 17 goals for the world's future can be achieved before 2030 with three unanimous principles fixed by United Nations such as Universality, Integration and Transformation.
1) End poverty in all its forms everywhere.
2) End hunger, achieve food security and improved nutrition and promote sustainable agriculture.
3) Ensure healthy lives and promote wellbeing for all at all ages.
4) Ensure inclusive and quality education for all and promote lifelong learning.
5) Achieve gender equality and empower women and girls.
6) Ensure access to water and sanitation for all.
7) Ensure access to affordable, reliable, sustainable and modern energy for all.
8) Promote inclusive and sustainable economic growth, employment and decent work for all.
9) Build resilient infrastructure, promote, sustainable industrialization and foster innovation.
10) Reduce inequality within and among countries.
11) Make cities inclusive, safe, resilient and sustainable.
12) Ensure sustainable consumption and production pattern.
13) Take urgent action to combat climate change and its impacts
14) Conserve and sustainably use the oceans, seas and marine resources.
15) Sustainably manage forests, combat desertification, stop and reverse land degradation, stop biodiversity loss.
16) Promote just, peaceful and inclusive societies.
17) Revitalize the global partnership for sustainable development.

Introduction:
1. Externality refers to external effects or spillover effects resulting from production or consumption on the third parties.
Definition:
1. It may be defined as "the cost or benefit imposed by the consumption and production activities of the individuals on the rest of the society not directly involved in these activity and towards which no payment is made".
Types:
1. Beneficial externalities are called "positive externalities".
2. Adverse externalities are called "negative externalities".
Positive Consumption Externality
1. When some residents of a locality hire a private security agency to patrol their area, the other residents of the area also benefit from better security without bearing cost.
Negative Consumption Externality
1. A person smoking cigarette gets satisfaction but this act causes dissatisfaction to the non-smokers who are driven to passive smoking.
Positive Production Externality
1. The ideal location for beehives is orchards.
2. While bees make honey, they also help in the pollination of apple blossoms.
3. The benefits. accrue to both producers (honey and apple).
4. This is called reciprocal untraded interdependency.
Negative Production Externality
1. They include pollution generated by a factory that imposes costs on others.
2. The emissions and effluents of a factory cause air and water pollution.
3. Water becomes contaminated and unfit for drinking (e.g.) Tanneries.
4. The innocent community bears the external cost for which it is not compensated.